Homogeneous Gold Catalysis
|
|
- Imogen Atkinson
- 5 years ago
- Views:
Transcription
1 1 omogeneous Gold Catalysis ighly Efficient Functionalization of C C Multiple Bonds and Electron-ich C Bonds 1% 61% yield C Et 1% ( 3 P)AuTf CE, rt, 50 min 95% yield Et 2 C AuL Et Michael. Krout Stoltz Group Literature Talk May 30, :1 d.r. 8pm, 147 oyes utline 1. Introduction a. istory b. A few basics of Au chemistry c. Some Au(I) and Au(III) organometallic complexes 2. Additions of carbon nucleophiles to activated C C multiple bonds a. Catalytic asymmetric aldol b. Stabilized carbon nucleophiles c. earrangements/cycloisomerization d. enol synthesis e. Arene nucleophilic additions (C functionalization) 3. eteroatom nucleophiles (also assisted) a. ydration/hydroamination b. eterocycle synthesis c. Annulation/napthylketone synthesis Select Au background references: Puddephatt,. The Chemistry of Gold; E. L. Sevier Scientific Publication Co., Amsterdam, ashmi, A. S. K. Gold Bulletin 2004, 37, Parish,. V. Gold Bulletin 1997, 30, Parish,. V. Gold Bulletin 1997, 30, Parish,. V. Gold Bulletin 1998, 31, Gimeno, M. C.; Laguna, A. Chem. ev. 1997, 97, Grohmann, A.; Schmidbaur,. Comprehensive rganometallic Chemistry II, 1995; vol. 3 pp 1-56.
2 2 Introduction Brief istory of Gold (circa BC) Gold is found in many minerals, including: quartz, nagyagite, calaverite, sylvanite, krennerite, pyrite and other sulfides (tellurides). Also found in veins in rocks or by sifting river beds. Elemental Gold is purified by extractive metalllurgy (using Cl2 sources) or by cyaniding: 4 Au 8 ac a[au(c)2] Zn 4 a[au(c)2] 4 a 2 ac Zn(C)2 Au (s) Gold is stable to oxygen and most corrosives, but is readily oxidized by Cl2 or dissolved in aqua regia, forming one of the most common gold complexes, AuCl4 (chlorauric acid). The most malleable element: 1 g can be beaten into a 1 m2 sheet (~ 230 atoms thick) Used in jewelry, denstistry, electronics, photography,coins, etc. Introduction Basic Principles of Gold Chemistry Au(I) and Au(III) are the most common oxidation states of Gold, with Au(III) being most prevalent Au is a soft metal, and therefore prefers soft ligands (e.g. 3P and carbanions): F < C2 < Cl < Br < I < S < 3P < Ar < hard soft Propensity for strong trans effect and trans influence trans effect: ability of L to labilize L trans to itself, directing incoming ligands to the trans position (kinetic effect) 3P > Cl trans influence: ability of a L to weaken the M L bond trans to itself in the ground state of the complex (thermodynamic effect) trans to Cl : ~ C6F5 > 3P > SPr2 ~ Cl
3 3 Introduction Basic Principles of Gold Chemistry Au organometallic complexes have a very low tendency to undergo!- elmination; Au complexes are very rare. Protodemetallation extremely fast; it is proposed that the Au-ate complex is protonated by acid, followed by reductive elimination. Weaker acids react more slowly for protonolysis of the Au C intermediate. Ar AuL Ar Ar AuL intermediate? Au(I) and Au(III) ligand exchange reactions are associative, and can occur at extremely high rates. Although Au complexes can undergo oxidative addition/reductive elimination, these processes are rare except for a few well defined cases. The lack of oxidation state change makes coupling chemistry (think Pd) difficult. Many mechanims proposed with the following chemistry, but it is important to note that in many cases the mechanism, and even the oxidation state of the catalytically active species are not known. Au(I) Complexes Au(I) complexes are d 10 and prefer to be linear, two-coordinate can be 3-coordinate trigonal planar can be 4-coordinate tetrahedral AuCl commercially available source of Au(I); exists as a polymeric chain with µ-cl L's Cl AuCl Au Cl n bench stable, but can reduce to Au(0) slowly: AuCl v. slow Au(0) Au 2 Cl 6 3 P can dissociate to form monomeric ( 3 P)AuCl a[aucl 4 ] 2 3P ( 3 P)AuCl AuCl 4 S 2 Cl P ( 3 P)AuCl elv. Chim. Acta. 1973, 56, 2405 Inorg. Synth. 1986, 24, 236
4 4 Au(I) Complexes [( 3 PAu) 3 ]BF 4 common source of electrophilic Au(I); useful in organometallic synthesis air and moisture stable ( 3 P)AuCl Ag 2 abf 4 [( 3 PAu) 3 ]BF 4 LAu readily prepared from L-stabilized Au(I) halide; bench stable complexes LAu Li or Mg LAu [( 3 PAu) 3 ]BF 4 1. Li or Mg 2. 2 workup LAu Inorg. Chem 1993, 32, 1946 J. rganomet. Chem. 1989, 369, 267 Cationic Au(I) Complexes Common methods for generation of LAu: 1. Ag, where = non-coordinating anion 2. LAuC 3 strong acid (e.g. 2 S 4, Ms, BF 4 ) 3. LAu BF 3 Et 2 4. [(LAu) 3 ]BF 4 BF 3 Et 2
5 5 Au(III) Complexes Au(III) complexes are d 8 and prefer to be square planar, four-coordinate; best known oxidation state commercially available source of Au(III); exists as a dimer(au 2 Cl 6 ) with µ-cl L's AuCl and aaucl the cheapest available source of Au(III) Au(0) aqua regia AuCl Et 2 or EtAc extraction 2. eutralize MAuCl M= a or K C C Bond Forming eactions Catalytic, Asymmetric Aldol C C 2 C 1% [Au(c-C 6 11 C) 2 ]BF 4 1% A C 2 Cl 2, 25 C h trans C 2 cis C 2 % yield trans/cis ratio %ee trans 98 89/ /16 72 c-ex 95 97/3 90 Fe P 2 P 2 2 t-bu /0 97 A Fe BF 4 2 P 2 Au C P 2 Proposed Transition State Model Ito, Y.; ayashi, T. JACS 1986, 108, 6405 Ito, Y. Chem. ev. 1992, 92, 857
6 C C Bond Forming eactions Catalytic, Asymmetric Aldol 6 C C 2 C 1% [Au(c-C 6 11 C) 2 ]BF 4 1% A C 2 Cl 2, 25 C h trans C 2 cis C 2 % yield trans/cis ratio %ee trans 98 89/ /16 72 c-ex 95 97/3 90 Fe P 2 P 2 2 t-bu /0 97 A 2 BF 4 trans/cis ratio %ee trans (C 2 ) /11 23 Fe P 2 Au C P 2 Fe P 2 P 2 (C 2 ) 2 69/ /32 racemic Proposed Transition State Model Ito, Y.; ayashi, T. JACS 1986, 108, 6405 Ito, Y. Chem. ev. 1992, 92, 857 C C Bond Forming eactions Catalytic, Asymmetric Aldol C C 2 C 1% [Au(c-C 6 11 C) 2 ]BF 4 1% A C 2 Cl 2, 25 C h trans C 2 cis C 2 % yield trans/cis ratio %ee trans 98 89/ /16 72 c-ex 95 97/3 90 t-bu /0 97 C 2 Cl C 2 2 Cl BF 4 2 P 2 Fe Au C P 2 Proposed Transition State Model LiAl 4 2 also see: Ito, Y.; ayashi, T. Tet. Lett. 1988, 29, 235 Lin, Y.-. Tet. Asymm. 1999, 10, 855
7 C C Bond Forming eactions Stabilized ucleophilic Addtions to Alkenes % AuCl 3 15% AgTf 3 1 C 2 Cl 2, rt, 5 h % yield 89 p-c m-clc Au Au 2 1 Au 2 70% 39% ( 3 P)AuCl or (c-exc)aucl showed decreased reactivity!-ketoesters reacted but gave a complex reaction mixture alkene added by syringe pump Au 3 Li, C.-J. JACS 2004, 126, 6884 C C Bond Forming eactions Conia-Ene 5-exo-dig Cyclization 1% ( 3 P)AuTf CE, rt, 15 min 94% yield 1% [( 3 PAu) 3 ]BF 4 5% Tf same result; AgTf gave no reaction no precaution to exclude air or moisture necessary substrate time product yield n = C 2 C 2 n= h 18 h 16 h C 2 n 90% 90% a 88% C 2 8 h 83% 5 min C 2 99% a 5% catalyst used Toste, F.. JACS 2004, 126, 4526
8 C C Bond Forming eactions Conia-Ene 5-exo-dig Cyclization 8 = Et 50 min 95% (17:1) = 24 h 86% (4.2:1) 1 h 95% (4:1) Bn Bn n-pr 1 h 97% n-pr diastereoselectivity implies some degree of ordering in the transition state Toste, F.. JACS 2004, 126, 4526 Conia-Ene 5-exo-dig Cyclization chanistic Considerations LAu mech A 2 C A AuL 2 C Ac AuL 2 C Ac LAu mech B 2 C B AuL 2 C Ac AuL ( 3 P)AuTf (90%) ( 3 P)AuTf (48%) Toste, F.. JACS 2004, 126, 4526
9 C C Bond Forming eactions 5-endo-dig Carbocyclization 9 1% ( 3 P)AuTf C 2 Cl 2, rt = allyl, 90% (10 min) propargyl, 96% (5 min) C 2 C 2 I 1 h, 88% =, 83% (1 h), 74% (15 min), 94% (15 min) 90% n n= 1, 93% 2, 76% 2 C AuL LAu C 2 A B disfavorable A 1,3 strain Toste, F.. ACIE 2004, 43, 5350 C C Bond Forming eactions Enyne Cycloisomerization- Theoretical Predictions Z 6-endo-dig Z 5-exo-dig Z Z Z M n a Z M n b Z M n Z d M n c Z 1,2- shift M n FT calculations predict 5-exo-dig cyclization transition state 6 kcal/mol lower in energy catalyzed by (P 3 )Au for terminal alkynes (pathway B). Z c Z d Echavarren, A. M. ACIE 2004, 43, 2402
10 C C Bond Forming eactions Enyne Cycloisomerization- Experimental bservations 10 2 S 2 S 2% ( 3 P)AuCl 2% AgSbF 6 C 2 Cl 2, rt, 5 min 100% yield 2 S 2 S as solvent a t (min) yield product yield 2 C 2 C 2 C 2 C 25 91% 2 C 2 C 97% 2 C 2 C 2 C 2 C 10 96% (4:1 E:Z) 2 C 2 C 2 C 2 C 5 76% 2 C 2 C 48% Echavarren, A. M. ACIE 2004,43, 2402 Echavarren, A. M. JACS 2001, 123, a eaction run with 3% ( 3 P)AuC 3 with acid co-catalyst (BF 4 or 3 PW ). eaction times are 4 and 12 h. C C Bond Forming eactions Enyne Cycloisomerization Synthesis of 1,3- and 1,4-dienes TIPS 1% AuCl C 2 Cl 2, 30 min 93% yield 2 TIPS TIPS (1,4:1,3) n-c 3 7 n-c 3 7 TIPS TIPS 73% 82% (6:1) TIPS TIPS 99% (4:1) 99% (3:1) n-c 5 11 TIPS TIPS 88% 84% Kozmin, S. A. JACS 2004, 126, 11806
11 Proposed chanism for Enyne Cycloisomerization for the Synthesis of 1,3- and 1,4-dienes TIPS TIPS AuCl TIPS 2 1 TIPS AuCl TIPS 2 = AuCl TIPS 2 = AuCl TIPS AuCl 2 1 TIPS AuCl 2 1 AuCl TIPS 2 1 TIPS AuCl Kozmin, S. A. JACS 2004, 126, C C Bond Forming eactions Catalyst ptimization for Enyne Cycloisomerization C 2 Cl 2, rt 1% catalyst catalyst conversion (C)PdCl 2, 24 h ~ 4% PtCl 2, 24 h ~ 4% PtCl 2, AgBF 4, 24 h ~ 5% AgBF 4, 24 h trace ( 3 P)AuCl, AgBF 4, 5 min 100% ( 3 P)AuCl, 24 h 0%, 3 h 50% 5%, 15% AgTf gave complete conversion but substantial decomposition Toste, F.. JACS 2004, 126, 10858
12 C C Bond Forming eactions Substrates for Enyne Cycloisomerization 12 substrate catalyst product yield (d.r.) 1% ( 3 P)AuSbF 6 95% Br Br 1% ( 3 P)AuSbF 6 94% Bn n-pr 1% ( 3 P)AuSbF 6 Bn n-pr 98% (>99:1) Bn Et 1% ( 3 P)AuSbF 6 Bn Et 96% (97:3) TIPS TIPS 97% ee 98:2 d.r. 3% ( 3 P)AuPF 6 99% (>99:1) 91% ee Toste, F.. JACS 2004, 126, C C Bond Forming eactions Proposed chanistic ypothesis cis trans LAu cis trans AuL cis trans AuL cis trans LAu cis trans 1% ( 3 P)AuPF 6 99% yield n cat. ( 3 P)AuBF 4 n= 1, 72% n= 2, 66% n Toste, F.. JACS 2004, 126, 10858
13 C C Bond Forming eactions Cationic Au(I) Propargyl-Claisen earrangement 13 1% catalyst, C 2 Cl 2 10 min, rt; ab 4 n-bu n-bu 95% ee cat= ( 3 P)AuBF 4, 85% (4% ee) [( 3 PAu) 3 ]BF 4, 91% (90% ee) TIPS 1% [( 3 PAu) 3 ]BF 4 C 2 Cl 2, 50min, rt; ab 4, n-bu n-bu 95% ee 81% yield 94%ee, >20:1 d.r. specificity occur when pseudoaxial avoids A 1,2 interaction with vinyl Au 1 1 Au Au Toste, F.. JACS 2004, 126, C C Bond Forming eactions enol Synthesis 1 1 2% C, 20 C % yield C 2 65 Ts 97 Ts 94 Ts 93 C(C 2 ) 2 88 (Ts)C 2 81 Pd(II), Pt(II) work, but very slowly rxn not sensitive to 2 or 2 up to 5 equiv 18 2 gave < 1% 18 incorporation =, Ts.. Ts 4% C Ts Ts ashmi, A. JACS 2000, 122, ashmi, A. rg. Lett. 2001, 3, % 51%
14 14 A B G ML n ML n ML n C ML n L n M E F L n M L n M A Primary Kinetic Isotope Effect was not observed. ashmi, A. S. K. ACIE 2005, 44, 2798 I J MLn K MLn L C C Bond Forming eactions enol Synthesis Ts Ts 5% Cl Au Cl G Ts G and observable by M at -20 C intermediate can be enriched up to 80% utilizing pyridine complex calculations of G and predict they are similar in energy (< 1 kcal/mol difference) Ts ashmi, A. S. K. ACIE 2005, 44, ray Structure
15 C C Bond Forming eactions Arene Functionalization % 7% AgTf CE,! 1 Br t-bu 83 C, 87% (5% ) 50 C, 83% 50 C, 76% 83 C, 69% 2.5% 7% AgTf CE, 50 C, 3 h 82% yield typical Lewis acids do not work cyclization is stereospecific open epoxide at primary carbon, S 2-like e, C. JACS 2004, 126, 5964 trans only C C Bond Forming eactions Electron-rich Arene Functionalization Tf 5% 15% AgTf CE, 120 C 90% yield arene electrophile yield (linear) yield (branched) n-butf 70% < 5% n-butf 40% 50% n-butf 10% 80% n-butf 5% 90% e, C. JACS 2004, 126, 13596
16 C C Bond Forming eactions Electron-rich Arene Functionalization- chanistic Insight 16 ArAuCl 2 n-butf (2 eq) 2 eq AgTf Ar 70% linear product by 7 days (no branched observed) n-butf 20% 60% AgTf CE, 120 C, 1 h; sat'd acl n-bu ~ 65% ~ 12% ~ 20% 5% 15% AgTf CE, 120 C = Ms =, 90%, < 15% e, C. JACS 2004, 126, C C Bond Forming eactions Arene Addition to Electron-deficient Alkynes Ar C 2 2.5% 7% AgTf neat, 23 C Ar C 2 C 2 C 2 Et C 2 Et Br 99% 75% 97% 80% highly Z-selective (only olefin isomer detected) cationic LAu(I) works as well: M. eetz Eur. JC 2003, 3485 immediate color change when arene and cationic complex mixed 1 5% 15% AgTf CE, 50 C 1 1 =, 84%, 99%, 73% e, C. JC 2004, 69, 3669
17 C C Bond Forming eactions Labeling and Crossover Experiments 17 C 3 3 C C 3 C 2 Et 5% 15% AgTf CE, rt C 3 () 3 C C 2 Et C 3 88% 97% yield Crossover Experiment () 86% yield 52%- 5% 15% AgTf CE, rt () 99% yield 48%- e, C. JC 2004, 69, 3669 C Bond Forming eactions irected ydration of Alkynes 5% aaucl : 2 (9:1) reflux A B time (h) product % yield n-c 5 11 n-c A a 79 C 3 n-c A a 75 n-c 6 13 C 3 C 3 10 A 70 n-c B 91 a Product isolated as a single olefin isomer (E). 100 n-bu h 91% yield 0 2h 67% yield h 99% yield conditions: 3% aaucl 4 2 2, : 2 (10:1), ultrasound 90 1h 92% yield % yield Utimoto, K. Bull. Chem. Soc. Jpn. 1991, 64, 2013 Utimoto, K. Tet. Lett. 1897, 28,
18 C Bond Forming eactions irected ydration of Alkynes - chanistic ypothesis 18 5% aaucl : 2 (9:1) reflux A B Au III Au III A when 1 = Au III Au III tautomerize B Utimoto, K. Bull. Chem. Soc. Jpn. 1991, 64, 2013 C Bond Forming eactions ydration of Alkynes 1 2 2% aaucl 4-2 (10:1) reflux 1 2 A 1 2 B 1 2 time (h) product % yield n-c A 91 (C 2 ) 9 n-c A 91 C 3 5 A:B (40:60) 94 C A:B (57:43) % yield 1 2 2% aaucl 4, reflux 1 h 1 2 n-c n-c 6 11 n-c reproducible on gram scale reduced to Au(0) during reaction, preventing lower catalyst loadings Utimoto, K. J. rg. Chem. 1991, 56, 3729
19 C Bond Forming eactions Efficient ydration of Propyne 19 3 C (L)Au C 3 S 2, 40 C L initial TF (h -1) T 3 As 430 Et 3 P P () 3 P 610 > ~ P Au 3 C 3 P Au C 3 C 3 FT predicts more stable over E- isomer by ~ 2.4 kcal/mol 3 C 3 P C 3 Au 3 P C 3 Au at low conversion, Z:E! 8:1 end of reaction, Z:E! 2:1 two -80 C in C 2 Cl 2 (CM, Ms - ) add, one singlet add alkyne, one singlet calculations predict alkyne to bind cation over by ~ 6 kcal/mol secondary alcohols reacts ~ 10x slower Teles, J.. ACIE 1998, 37, 1415 C Bond Forming eactions Efficient ydration of Alkynes n-ex 0.01% ( 3 P)Au 50 mol% acid, additive - 2 (10:1) 1 h, 70 C n-ex acid additive % yield 2 S 4 2 S 4 35 C (1atm) 99 C 3 S PW w/o additional L, catalyst decomposition observed (particles) 2 S 4 conditions w/o added L C 3 n-pr n-pr 1% cat. 90% yield 0.2% cat 83% yield 0.2% cat 95% yield 42% yield 32% yield 0.2% cat. Tanaka, M. ACIE 2002, 41, 4563
20 C Bond Forming eactions Alcohol Addition onto Unactivated Terminal lefins 20 2% 3 PAuCl 2% AgTf, 85 C (4 eq) 84% yield Bn 15 1 =, 78% C 2, 68% 84% (5% cat) 1 BnC =, 71%, 80% (15:1) 75% (5% cat) 5.5:1 >95% yield 1% 3 PAuTf, 20 h, 85 C 75% conversion E:Z = 2.2:1 e, C. JACS 2005, 127, 6966 C Bond Forming eactions Intramolecular Trapping of Enyne Cycloisomerization Adduct with eteroatom ucleophile 5% C, 20 C 89% yield Ts Ts 89% yield ( 3 P)AuCl AgCl 4 82% yield 87% yield ( 3 P)AuCl AgCl 4 96% yield ( 3 P)AuCl AgCl 4 Kozmin, S. A. JACS 2005, 127, 6962
21 C Bond Forming eactions Intramolecular Trapping of Enyne Cycloisomerization Adduct with eteroatom ucleophile 21 10% C, 20 C 90% yield 10% C, 20 C 90% yield Kozmin, S. A. JACS 2005, 127, 6962 C Bond Forming eactions chanistic ationale or Kozmin, S. A. JACS 2005, 127, 6962
22 C Bond Forming eactions ydroamination of Alkynes % ( 3 P)Au % 3 PW neat, 70 C, 1-2 h % yield C 6 5 C BrC CC P Au P Au 2-C 4 3 S C A B n-c 3 7 C 3 4-BrC C 6 5 C internal alkynes less reactive (sterics?) reaction proceeds more smoothly if 1. amine is more electron withdrawing 2. alkyne is more electron donating Tanaka, M. rg. Lett. 2003, 5, 3349 Au(I) calculations predict B Attack by mode of A used to rationalize Au(III) amine additions (tetrahydropyridine synthesis) EW amine as a better reactant supports B Utimoto, K. eterocycles 1987, 25, 297 Utimoto, K. Synthesis 1991, 975 C Bond Forming eactions Indole Synthesis 2 4% aaucl Et or Et- 2 rt, 5 h 84% yield Au(III) salts gave best yields, AuCl (50%), PtCl 4 (20%), various Pd(II) and Cu(II) gave < 10%. t-bu 2 h, 83% 4 h, 80% S Cl Cl 20 h, 90% 2 Cl F 3 C 16 h, 66% 16 h, 60% Marinelli, F. Synthesis 2004, 4, 610
23 C, Bond Forming eactions Isoxazole Synthesis 23 5%, a 2 1 3, 2 50 C t (h) % yield 5 40 Bu 1 38 Bn 2 CC 2 C BzC 2 C Cl 3 Au 2 AuCl 2 Cl 1 Cl 3 Au Gasparrini, F. JACS 1993, 115, 4401 C Bond Forming eactions xazole Synthesis 5% C or C 2 Cl 2 rt t (h) % yield 12 >95 12 >95 20 > stereospecific addition of oxygen to activated alkyne 5% can be enriched up to 95% before isomerization to oxazole stable for weeks at -25 C * 2 C ashmi, A. S. K. L 2004, 6, 4391
24 C Bond Forming eactions Furan Synthesis 24 Et Et or Et Et 0.1% minutes, C quantitative Et Et 0.1% C, 1 h PMB 1% C 74% yield PMB 1% 61% yield C Ag(I) very slow reaction, PdCl 2 (C) 2 took about an hour ashmi, A. S. K. ACIE 2000, 39, 2285 C Bond Forming eactions Furan Synthesis 1 1% 1 u, C 2 Cl 2 rt, 1 h uc alkenynone u product alkenynone u product 1 = 62% 1 = 63% (1.2:1 d.r.) 1 = Larock,. JACS 2004, 126, % 90% Bn 63% Bn Bn 34% 40%
25 C Bond Forming eactions Furan Synthesis chanistic ationale 25 Cl 3 Au Michael Addition u A B u u u u 1% does not catalyze addition u to cyclohexenone or methylvinyl ketone under the specified conditions. Larock,. JACS 2004, 126, Assisted Bond Forming eactions Cyclopentanone Synthesis t-bu 2 2-5% ( 3 P)AuTf C, rt n-bu n-bu n-bu Ts 8 h, 80% 20 h, 85% 20 h, 81% 14 h, 45% 10 h, 48% conditions: 5% ( 3 P)AuSbF 6 C, -20 C % yield SM % ee Product % ee Toste, F.. JACS 2005, 127, 5802
26 -Assisted Bond Forming eactions Cyclopentanone Synthesis t-bu Piv LAu 3 Piv 3 LAu 3 t-bu 2 AuL 3 isolated Cp intermediate mixture of E:Z olefins gives selective reaction of E isomer only (recover Z) AuL 2 3 t-bu Toste, F.. JACS 2005, 127, Assisted Bond Forming eactions apthylketone Synthesis % CE, 80 C 2-6 h A B A:B ratio % yield n-c : :<1 96 Si 3 16:84 82 CC 3 <1:99 75 Si 3 99:<1 92 when 3 = M evidence for substitution patter n-c :8 91 other solvents work (EtAc, dioxane, C) no reaction w/o Yamamoto, Y. JACS 2002, 124, 12650
27 -Assisted Bond Forming eactions apthylketone chanistic ypothesis A Cl 3 Au step-wise intermediate possible Yamamoto, Y. JACS 2002, 124, Assisted Bond Forming eactions apthylketone chanistic ypothesis 3% CE, 80 C =, 40%, 60% 3% C, 80 C, 3 h 57% yield 3%, 2 C, 80 C, 3 h 61% yield Yamamoto, Y. JACS 2002, 124, yker, G. ACIE 2003, 42, 4399
Homogeneous Gold Catalysis - Unique Reactivity for Activation of C C Multiple Bonds
1 rganic Seminar 2011.05.09 omogeneous Gold Catalysis - Unique Reactivity for Activation of C C Multiple Bonds ysical rganic Chemistry Laboratory (Nakamura Laboratory) D2 Masaki Sekine Development of Gold
More informationAdditions to Metal-Alkene and -Alkyne Complexes
Additions to tal-alkene and -Alkyne Complexes ecal that alkenes, alkynes and other π-systems can be excellent ligands for transition metals. As a consequence of this binding, the nature of the π-system
More informationStable gold(iii) catalysts by oxidative addition of a carboncarbon
Stable gold(iii) catalysts by oxidative addition of a carboncarbon bond Chung-Yeh Wu, Takahiro oribe, Christian Borch Jacobsen & F. Dean Toste ature, 517, 449-454 (2015) presented by Ian Crouch Literature
More informationAsymmetric Synthesis of Medium-Sized Rings by Intramolecular Au(I)-Catalyzed Cyclopropanation
Asymmetric Synthesis of Medium-Sized ings by Intramolecular Au(I)-Catalyzed Cyclopropanation 1 2 Iain D. G. Watson, Stefanie itter, and F. Dean Toste JACS, ASAP, 1/22/2009 DI: 10.1021/ja8085005 2.5 mol%
More informationOlefin Metathesis ROMP. L n Ru= ROMP n RCM. dilute
lefin Metathesis MP: ing-opening metathesis polymerization Thermodynamically favored for 3,4, 8, larger ring systems Bridging groups (bicyclic olefins) make ΔG polymerization more favorable as a result
More informationElectrophilic Carbenes
Electrophilic Carbenes The reaction of so-called stabilized diazo compounds with late transition metals produces a metal carbene intermediate that is electrophilic. The most common catalysts are Cu(I)
More informationZr-Catalyzed Carbometallation
-Catalyzed Carbometallation C C C C ML n C C ML n ML n C C C C ML n ML n C C ML n Wipf Group esearch Topic Seminar Juan Arredondo November 13, 2004 Juan Arredondo @ Wipf Group 1 11/14/2004 Carbometallation
More informationMetal Catalyzed Outer Sphere Alkylations of Unactivated Olefins and Alkynes
Metal Catalyzed uter Sphere Alkylations of Unactivated lefins and Alkynes Stephen Goble rganic Super-Group Meeting Literature Presentation ctober 6, 2004 1 utline I. Background Introduction to Carbometallation
More informationOC 2 (FS 2013) Lecture 3 Prof. Bode. Redox Neutral Reactions and Rearrangements
C 2 (F 203) Lecture 3 Prof. Bode edox eutral eactions and earrangements Types of edox eutral rganic eactions. eactions with no external reducing or oxidizing agent In this case, one part of the starting
More informationMolybdenum-Catalyzed Asymmetric Allylic Alkylation
Molybdenum-Catalyzed Asymmetric Allylic Alkylation X MoL n u u * Tommy Bui 9/14/04 Asymmetric Allylic Alkylation from a Synthetic Viewpoint X X M u u * and/or u form a C-C bond with the creation of a new
More informationChiral Brønsted Acid Catalysis
Chiral Brønsted Acid Catalysis Aryl Aryl Aryl Aryl S CF 3 2 P Fe CF 3 CF 3 2 Jack Liu ov. 16, 2004 CF 3 Introduction Chiral Brønsted acid catalysis in nature: enzymes and peptides Chiral Brønsted acid
More informationStrained Molecules in Organic Synthesis
Strained Molecules in rganic Synthesis 0. Introduction ~ featuring on three-membered rings ~ Tatsuya itabaru (M) Lit. Seminar 08068 for cyclobutadienes : see Mr. Yamatsugu's Lit. Sem. 069 eat of Formation
More informationChapter 4 Electrophilic Addition to Carbon Carbon Multiple Bonds 1. Addition of H X 2. Addition of H OH and addition of Y X 3. Addition to allene and
Chapter 4 Electrophilic Addition to Carbon Carbon Multiple Bonds 1. Addition of X 2. Addition of and addition of Y X 3. Addition to allene and alkyne 4. Substitution at α-carbon 5. eactions via organoborane
More informationπ-alkyne metal complex and vinylidene metal complex in organic synthesis
Literature Seminar 080220 Kenzo YAMATSUGU (D1) π-alkyne metal complex and vinylidene metal complex in organic synthesis 0. Introduction ' ' = π-alkyne metal complex vinylidene metal complex ecently, electrophilic
More informationOrganometallic Chemistry and Homogeneous Catalysis
rganometallic hemistry and omogeneous atalysis Dr. Alexey Zazybin Lecture N8 Kashiwa ampus, December 11, 2009 Types of reactions in the coordination sphere of T 3. Reductive elimination X-L n -Y L n +
More informationVI. Metal alkyls from oxidative addition / insertion
V. Metal alkyls from oxidative addition / insertion A. Carbonylation - C insertion very facile, metal acyls easily cleaved, all substrates which undergo oxidative addition can in principle be carbonylated.
More informationChem 253 Problem Set 7 Due: Friday, December 3, 2004
Chem 253 roblem Set 7 ue: Friday, ecember 3, 2004 Name TF. Starting with the provided starting material, provide a concise synthesis of. You may use any other reagents for your synthesis. It can be assumed
More informationChiral Catalyst II. Palladium Catalysed Allylic Displacement ( -allyl complexes) 1. L n Pd(0) 2. Nuc
Chiral Catalyst II ast lecture we looked at asymmetric catalysis for oxidation and reduction Many other organic transformations, this has led to much investigation Today we will look at some others...
More informationRecent Advances in the Chemistry of Alleneamides. Denmark Group Meeting Nate Duncan-Gould
Recent Advances in the hemistry of Alleneamides Denmark Group eting ate Duncan-Gould 9-25-07 allene The Structure allenamine ummulenes!!! X X X!!! X X ummulene omparison of M s FM at PM3 level M LUM alculated
More informationO + k 2. H(D) Ar. MeO H(D) rate-determining. step?
ame: CEM 633: Advanced rganic Chem: ysical Problem Set 6 (Due Thurs, 12/8/16) Please do not look up references until after you turn in the problem set unless otherwise noted. For the following problems,
More informationAnswers To Chapter 7 Problems.
Answers To Chapter Problems.. Most of the Chapter problems appear as end-of-chapter problems in later chapters.. The first reaction is an ene reaction. When light shines on in the presence of light and
More informationLiterature Report III
Literature Report III Regioselective ydroarylation of Alkynes Reporter: Zheng Gu Checker: Cong Liu Date: 2017-08-28 Cruz, F. A.; Zhu, Y.; Tercenio, Q. D.; Shen, Z.; Dong, V. M. J. Am. Chem. Soc. 2017,
More informationElementary Organometallic Reactions
Elementary eactions CE 966 (Tunge) Elementary rganometallic eactions All mechanisms are simply a combination of elementary reactions. 1) Coordination -- issociation 2) xidative Addition -- eductive Elimination
More informationDenmark s Base Catalyzed Aldol/Allylation
Denmark s Base Catalyzed Aldol/Allylation Evans Group Seminar ovember 1th, 003 Jimmy Wu Lead eferences: Denmark, S. E. Acc. Chem. es., 000, 33, 43 Denmark, S. E. Chem. Comm. 003, 167 Denmark, S. E. Chem.
More informationThree Type Of Carbene Complexes
Three Type f arbene omplexes arbene complexes have formal metal-to-carbon double bonds. Several types are known. The reactivity of the carbene and how it contributes to the overall electron counting is
More informationChap 11. Carbonyl Alpha-Substitution Reactions and Condensation Reactions
Chap 11. Carbonyl Alpha-Substitution eactions and Condensation eactions Four fundamental reactions of carbonyl compounds 1) Nucleophilic addition (aldehydes and ketones) ) Nucleophilic acyl substitution
More informationHighlights of Schmidt Reaction in the Last Ten Years
ighlights of Schmidt eaction in the Last Ten Years Dendrobates histrionicus Jack Liu ov. 18, 2003 Introduction Classical Schmidt reaction of aldehydes and carboxylic acids Classical Schmidt reaction of
More information[3,3]-sigmatropic Processes. [2,3]-sigmatropic Processes. Ene Reactions. Generalized Sigmatropic Processes X,Y=C, N, O, S X,Y=C, N, O, S
Generalized igmatropic Processes [3,3]-sigmatropic Processes 1 3,=C,,, 1 3 3,=C,,, 3 [2,3]-sigmatropic Processes 1 3,=C,,, 1 3 Ene eactions 1 3 1 3 Cope earrangement [3,3]- igmatropic earrangements Transition
More informationFunctionalization of terminal olefins via H migratory insertion /reductive elimination sequence Hydrogenation
M.C. White, Chem 153 verview -282- Week of ovember 11, 2002 Functionalization of terminal olefins via migratory insertion /reductive elimination sequence ydrogenation ML n E ydrosilylation Si 3 Si 3 ML
More informationNucleophilic attack on ligand
Nucleophilic attack on ligand Nucleophile "substitutes" metal hapticity usually decreases xidation state mostly unchanged Competition: nucleophilic attack on metal usually leads to ligand substitution
More informationSynthetic Methodology. Using Tertiary Phosphines. as Nucleophilic Catalysts
Synthetic Methodology Using Tertiary osphines as Nucleophilic Catalysts 1 3 2 u 2 (P 3 ) 3 4 1 2 D. Ma, X. Lu 1988 1 2 Pd 2 (dba) 3.CCl 3 /P 3 /Ac or Pd(Ac) 2 /P 3 1 2 B. M. Trost 1988 1 3 2 u 2 (P 3 )
More informationLecture 6: Transition-Metal Catalysed C-C Bond Formation
Lecture 6: Transition-Metal Catalysed C-C Bond Formation (a) Asymmetric allylic substitution 1 u - d u (b) Asymmetric eck reaction 2 3 Ar- d (0) Ar 2 3 (c) Asymmetric olefin metathesis alladium π-allyl
More informationOxidative Addition/Reductive Elimination 1. Oxidative Addition
Oxidative Addition Oxidative Addition/Reductive Elimination 1 An oxidative addition reaction is one in which (usually) a neutral ligand adds to a metal center and in doing so oxidizes the metal, typically
More informationChapter 14. Principles of Catalysis
Organometallics Study Meeting 2011/08/28 Kimura Chapter 14. Principles of Catalysis 14. 1. General Principles 14.1.1. Definition of a Catalyst 14.1.2. Energetics of Catalysis 14.1.3. Reaction Coordinate
More informationDirect, Catalytic Hydroaminoalkylation of Unactivated Olefins with N-Alkyl Arylamines
Current Literature - May 12, 2007 Direct, Catalytic ydroaminoalkylation of Unactivated lefins with -Alkyl ylamines ' '' Ta[ 2 ] 5 (4-8 mol%), 160-165 o C 24-67h 66-95% ' '' S. B. erzon and J. F. artwig,
More informationCopper-Catalyzed Synthesis of Esters from Ketones. Alkyl Group as a Leaving Group.
Copper-Catalyzed Synthesis of Esters from Ketones. Alkyl Group as a Leaving Group. akatani, Y.; Koizumi, Y.; Yamasaki, R.; Saito, S. rg. Lett. 2008, 10, 2067-2070. An Annulation Reaction for the Synthesis
More informationCarbenes and Carbene Complexes I Introduction
Carbenes and Carbene Complexes I Introduction A very interesting (honest) class of radical-like molecules Steadily becoming more important as they find far more synthetic applications We will primarily
More informationMild Cobalt-Catalyzed Hydrocyanation of Olefins with Tosyl Cyanide
Mild Cobalt-Catalyzed ydrocyanation of lefins with Tosyl Cyanide 1 3 2 + Ts Co cat., Si 3 Et, 1-3 h, T 1 2 3 Gaspar, B.; Carreira, E. M. Angew. Chem. Int. Ed. ASAP Current Literature Kalyani Patil 12 May
More informationShi Asymmetric Epoxidation
Shi Asymmetric Epoxidation Chiral dioxirane strategy: R 3 + 1 xone, ph 10.5, K 2 C 3, H 2, C R 3 formed in situ catalyst (10-20 mol%) is prepared from D-fructose, and its enantiomer from L-sorbose oxone,
More informationCHEM 251 (4 credits): Description
CHEM 251 (4 credits): Intermediate Reactions of Nucleophiles and Electrophiles (Reactivity 2) Description: An understanding of chemical reactivity, initiated in Reactivity 1, is further developed based
More informationCuI CuI eage lic R tal ome rgan gbr ommon
Common rganometallic eagents Li Et 2 Li Mg Et 2 Li alkyllithium rignard Mg Mg Li Zn TF ZnCl 2 TF dialkylzinc Zn 2 2 Zn Li CuI TF ganocuprate CuI 2 2 CuI common electrophile pairings ' Cl ' '' ' ' ' ' '
More informationsp 3 C-H insertion by α-oxo Gold Carbene B4 Kei Ito
1 sp 3 C-H insertion by α-oxo Gold Carbene B4 Kei Ito 2016. 1. 30 1. Introduction 2 About Carbene 3 Brief history of carbene (~2000) Carbene Neutral compounds featuring a divalent carbon atom with only
More informationAsymmetric Catalysis by Lewis Acids and Amines
Asymmetric Catalysis by Lewis Acids and Amines Asymmetric Lewis acid catalysis - Chiral (bisooxazoline) copper (II) complexes - Monodentate Lewis acids: the formyl -bond Amine catalysed reactions Asymmetric
More informationReaction chemistry of complexes Three general forms: 1. Reactions involving the gain and loss of ligands a. Ligand Dissoc. and Assoc. (Bala) b.
eaction chemistry of complexes Three general forms: 1. eactions involving the gain and loss of ligands a. Ligand Dissoc. and Assoc. (Bala) b. Oxidative Addition c. eductive Elimination d. Nucleophillic
More informationLewis Base Catalysis: the Aldol Reaction (Scott Denmark) Tom Blaisdell Friday, January 17 th 2014 Topic Talk
Lewis Base Catalysis: the Aldol eaction (Scott Denmark) Tom Blaisdell Friday, January 17 th 2014 Topic Talk Scott E. Denmark 1975 - S.B. in Chemistry MIT (ichard. olm and Daniel S. Kemp) 1980 - D.Sc in
More informationOxidative Addition and Reductive Elimination
xidative Addition and Reductive Elimination red elim coord 2 ox add ins Peter.. Budzelaar xidative Addition Basic reaction: n + X Y n X Y The new -X and -Y bonds are formed using: the electron pair of
More informationCatalytic Asymmetric [4+1] Annulation of Sulfur Ylides with Copper Allenylidene Intermediates. Reporter: Jie Wang Checker: Shubo Hu Date: 2016/08/02
Catalytic Asymmetric [4+1] Annulation of Sulfur Ylides with Copper Allenylidene Intermediates Reporter: Jie Wang Checker: Shubo Hu Date: 2016/08/02 Xiao, W.-J. et al. J. Am. Chem. Soc. 2016, 138, 8360.
More informationAsymmetric Nucleophilic Catalysis
Asymmetric ucleophilic Catalysis Chiral catalyst X 2 Chiral catalyst X = alkyl, X 1 2 1 Vedejs, E.; Daugulis,. J. Am. Chem. Soc. 2003, 125, 4166-4173 Shaw, S. A.; Aleman,.; Vedejs, E. J. Am. Chem. Soc.
More informationOrganometallic Rections 1: Reactions at the Metal
E Organometallic Rections 1: Reactions at the Metal Three major classes of reactions: 1 Ligand Substitution associative (cf. S N 2) dissociative (cf. S N 1) interchange (not dealt with in this course)
More informationNuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320 I. Isolated, cumulated, and conjugated dienes A diene is any compound with two or C=C's is a diene. Compounds containing more than two
More informationIridium-Catalyzed Hydrogenation with Chiral P,N Ligands
Iridium-Catalyzed Hydrogenation with Chiral P, Ligands 贾佳 utline Brief Introduction Hydrogenation of C=C Bonds Hydrogenation of C= Bonds Hydrogenation of C= Bonds Conclusion Brief Introduction First example
More informationNegishi Coupling of Secondary Alkylzinc Halides with Aryl Bromides and Chlorides
Negishi Coupling of Secondary Alkylzinc alides with Aryl Bromides and Chlorides X X = Br, Cl 2 1 ZnBr 1, 2 = Alkyl Cat. Pd(OAc) 2 Ligand TF/Toluene rt or 60 o C 1 2 J. Am. Chem. Soc. 2009, ASAP Article
More informationChapter 3. Alkenes And Alkynes
Chapter 3 Alkenes And Alkynes Alkenes ydrocarbons containing double bonds C C double bond the functional group center of reactivity Molecular Formula of Alkene Acyclic alkene: C n 2n Cyclic alkene: C n
More informationMechanism Problem. 1. NaH allyl bromide, THF N H
Mechanism Problem 1. a allyl bromide, TF 2. 9-BB (1.2 equiv), TF, rt; ame (1.2 equiv); t-buli (2.4 equiv), TMEDA (2.4 equiv) 30 to rt; allyl bromide; 30% 2 2, aq. a, 0 C (58% yield) Mechanism Problem 9-BB
More informationAldehydes and Ketones : Aldol Reactions
Aldehydes and Ketones : Aldol Reactions The Acidity of the a Hydrogens of Carbonyl Compounds: Enolate Anions Hydrogens on carbons a to carbonyls are unusually acidic The resulting anion is stabilized by
More informationAdvanced Organic Chemistry
D. A. Evans, G. Lalic Question of the day: Chemistry 530A TBS Me 2 C Me toluene, 130 C 70% TBS C 2 Me H H Advanced rganic Chemistry Me Lecture 16 Cycloaddition Reactions Diels _ Alder Reaction Photochemical
More informationCHEM 203. Final Exam December 15, 2010 ANSWERS. This a closed-notes, closed-book exam. You may use your set of molecular models
CEM 203 Final Exam December 15, 2010 Your name: ANSWERS This a closed-notes, closed-book exam You may use your set of molecular models This test contains 15 pages Time: 2h 30 min 1. / 16 2. / 15 3. / 24
More informationRadical Reactions. Radical Stability!!! bond dissociation energies X Y X + Y. bond BDE (kcal/mol) bond BDE (kcal/mol) CH 3 CH 3 CH 2 95 O H R 2 C H
adical eactions adical Stability!!! bond dissociation energies X Y X Y bond BDE (kcal/mol) bond BDE (kcal/mol) C 3 104 108 C 3 C 2 98 110 95 2 C 102 (-) 93 (C-) 92 C 3 C 3 36 89 85 C 3 C 3 80 adical eactions
More informationO CH 3. Mn CH 3 OC C. 16eelimination
igratory Insertion igratory Insertion/Elimination 1 A migratory insertion reaction is when a cisoidal anionic and neutral ligand on a metal complex couple together to generate a new coordinated anionic
More informationLecture Notes Chem 51B S. King I. Conjugation
Lecture Notes Chem 51B S. King Chapter 16 Conjugation, Resonance, and Dienes I. Conjugation Conjugation occurs whenever p-orbitals can overlap on three or more adjacent atoms. Conjugated systems are more
More information2.222 Practice Problems 2003
2.222 Practice Problems 2003 Set #1 1. Provide the missing starting compound(s), reagent/solvent, or product to correctly complete each of the following. Most people in the class have not done this type
More informationSome Hartwig Chemistry Experimental Approaches and Detailed Mechanistic Analysis
Some artwig Chemistry Experimental Approaches and Detailed chanistic Analysis b. 1964 1986 A.B. Princeton U, Maitland Jones 1990.D. UC Berkeley, obert Bergman and ichard Anderson 1990-92 Post-doc, MIT,
More informationChiral Bronsted Acids as Catalysts
Chiral Bronsted Acids as Catalysts Short Literature Seminar 6/3/08 Dustin aup BIL Derived osphoric Acids - First reported in 1992 as a ligand by irrung and coworkers. 4 h 2 irrung Tet. Lett. 1992, 33,
More informationStereoselective reactions of the carbonyl group
1 Stereoselective reactions of the carbonyl group We have seen many examples of substrate control in nucleophilic addition to the carbonyl group (Felkin-Ahn & chelation control) If molecule does not contain
More informationOnly five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those five.
Chem 232 D. J. Wardrop wardropd@uic.edu Problem Set 6 Answers Question 1. nly five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those
More informationCH 3 TMG, DMF N H 3 CO 2 S. (PPh 3 ) 2 Pd 0
1. (a) rovide a reasonable mechanism for the following transformation. I S 2 C 3 C 3 ( 3 ) 2 2, CuI C 3 TMG, DMF 3 C 2 S TMG = Me 2 Me 2 ICu ( 3 ) 2 0 I S 2 C 3 S 2 C 3 Cu I 3 3 3 C 2 S I 3 3 3 C 2 S 3
More informationCHEM 330. Final Exam December 5, 2014 ANSWERS. This a closed-notes, closed-book exam. The use of molecular models is allowed
CEM 330 Final Exam December 5, 2014 Your name: ASWERS This a closed-notes, closed-book exam The use of molecular models is allowed This exam consists of 12 pages Time: 2h 30 min 1. / 30 2. / 30 3. / 30
More information1. Addition of HBr to alkenes
eactions of Alkenes I eading: Wade chapter 8, sections 8-1- 8-8 tudy Problems: 8-47, 8-48, 8-55, 8-66, 8-67, 8-70 Key Concepts and kills: Predict the products of additions to alkenes, including regiochemistry
More informationHomogeneous Catalysis - B. List
omogeneous Catalysis - B. List 2.2.2 Research Area "rganocatalytic Asymmetric α-alkylation of Aldehydes" (B. List) Involved:. Vignola, A. Majeed Seayad bjective: α-alkylations of carbonyl compounds are
More informationInsertion Reactions. 1) 1,1 insertion in which the metal and the X ligand end up bound to the same (1,1) atom
Insertion Reactions xidative addition and substitution allow us to assemble 1e and 2e ligands on the metal, respectively. With insertion, and its reverse reaction, elimination, we can now combine and transform
More informationCatalysis by Group IV Elements CHEM 966 (Tunge) Good reference: Titanium and Zirconium in Organic Synthesis Ilan Marek Ed., 2002.
Catalysis by Group IV Elements CEM 966 (Tunge) Good reference: Titanium and Zirconium in rganic Synthesis Ilan Marek Ed., 2002. Electronegativity: Ti(1.54); (1.33); f(1.3) Much of the chemistry is dominated
More informationCationic Phosphine-Gold(I) Catalysis for C-C Forming Reaction with C C ~ Can relativistic effects rationalize its reactivity? ~
iterature Seminar (D2 part) 071114 (wed) Wataru Itano (D2) page 1 Cationic Phosphine-Gold(I) Catalysis for C-C Forming eaction with C C ~ Can relativistic effects rationalize its reactivity? ~ @ Carbometallation
More informationCatalytic Asymmetric Pauson-Khand Reaction. Won-jin Chung 02/25/2003
Catalytic Asymmetric Pauson-Khand eaction U. Khand; G.. Knox; P. L. Pauson; W. E. Watts J. Chem. Soc. Chem. Commun. 1971, 36 Won-jin Chung 02/25/2003 The General Pattern of the Pauson-Khand eaction Co
More informationCourse 201N 1 st Semester Inorganic Chemistry Instructor: Jitendra K. Bera
andout-9 ourse 201N 1 st Semester 2006-2007 Inorganic hemistry Instructor: Jitendra K. Bera ontents 3. rganometallic hemistry xidative Addition, Reductive Elimination, Migratory Insertion, Elimination
More informationIntramolecular Ene Reactions Utilizing Oxazolones and Enol Ethers Fisk, J.S. and Tepe, J..J J. Am. Chem. Soc., 2007, 129,
Intramolecular Ene Reactions Utilizing xazolones and Enol Ethers Fisk, J.S. and Tepe, J..J J. Am. Chem. Soc., 2007, 129, 3058-3059 - versus -Arylation of Aminoalcohols: rthogonal Selectivity in Copper-Based
More informationDirect Oxidative Heck Cyclizations: Intramolecular Fujiwara-Moritani Arylations for the Synthesis of Functionalized Benzofurans and Dihydrobenzofurans
Direct xidative eck Cyclizations: Intramolecular Fujiwara-Moritani Arylations for the Synthesis of Functionalized Benzofurans and Dihydrobenzofurans by Zhang,.; Ferreira, E. M.; Stoltz, B. M. Angewandte
More informationSuggested solutions for Chapter 40
s for Chapter 40 40 PBLEM 1 Suggest mechanisms for these reactions, explaining the role of palladium in the first step. Ac Et Et BS () 4 2 1. 2. K 2 C 3 evision of enol ethers and bromination, the Wittig
More informationChapter 20: Aldehydes and Ketones
hapter 20: Aldehydes and Ketones [hapter 20 Sections: 20.1-20.7, 20.9-10.10, 20.13] 1. Nomenclature of Aldehydes and Ketones ketone ' aldehyde 2. eview of the Synthesis of Aldehydes and Ketones Br Br f
More informationLigand Substitution Reactivity of Coordinated Ligands
Reactivity of Coordinated Ligands 2 C 2 H 4 (0) + H + + + 2 2 e (Cu 2 Cu) H CH 3 CH H "βh elim" ins βh elim H Peter H.M. Budzelaar Why care about substitution? Basic premise about metalcatalyzed reactions:
More informationRhodium Carbenoids and C-H Insertion
hodium Carbenoids and C- Insertion Literature Talk Uttam K. Tambar March 1, 2004 8pm, oyes 147 h h h h h h irreversible reversible carbenoid 2 h2l4 1 h2l4 or h2l4 2 utline I. What is a Carbene? II. What
More informationChapter 2 The Elementary Steps in TM Catalysis
hapter 2 The Elementary Steps in TM atalysis + + ligand exchange A oxidative addition > n + A B n+2 reductive elimination < B n n+2 oxidative coupling + M' + M' transmetallation migratory insertion > (carbo-,
More informationA. Loupy, B.Tchoubar. Salt Effects in Organic and Organometallic Chemistry
A. Loupy, B.Tchoubar Salt Effects in Organic and Organometallic Chemistry 1 Introduction - Classification of Specific Salt Effects 1 1.1 Specific Salt Effects Involving the Salt's Lewis Acid or Base Character
More informationFunctionalization of C(sp 3 ) H Bonds Using a Transient Directing Group
Literature eport Functionalization of C(sp 3 ) Bonds Using a Transient Directing Group eporter: Mu-Wang Chen Checker: Yue Ji Date: 2016-04-05 Yu, J.-Q. et al. Science 2016, 351, 252-256. Scripps esearch
More informationS N 1 Displacement Reactions
S N 1 Displacement Reactions Tertiary alkyl halides cannot undergo S N 2 reactions because of the severe steric hindrance blocking a backside approach of the nucleophile. They can, however, react via an
More informationLewis Base Activation of Lewis Acids: Development of a Lewis Base Catalyzed Selenolactonization
Lewis Base Activation of Lewis Acids: Development of a Lewis Base Catalyzed Selenolactonization Denmark, S.E. and Collins, W.R. rg. Lett. 2007, 9, 3801-3804. C 2 H + Se Lewis Base CH 2 Cl 2 Se Presented
More informationTips for taking exams in 852
Comprehensive Tactical Methods in rganic Synthesis W. D. Wulff 1) Know the relative reactivity of carbonyl compounds Tips for taking exams in 852 Cl > > ' > > ' N2 eg: 'Mg Et ' 1equiv. 1equiv. ' ' Et 50%
More informationdeactivation or decomposition is therefore quantified using the turnover number.
A catalyst may be defined by two important criteria related to its stability and efficiency. Name both of these criteria and describe how they are defined with respect to stability or efficiency. A catalyst
More informationTMSCl imidazole DMF. Ph Ph OTMS. Michael reaction. Michael reaction Ph R 3. epoxidation O R
eaction using diarylprolinol silyl ether derivatives as catalyst 1) C Et K C 3, ) MgBr, TF TMS hexane, 0 o C TBS p- C 6 4, T C Et 85%, 99% ee Angew. Chem., nt. Ed., 44, 41 (005). rg. Synth., 017, 94, 5.
More informationCHAPTER 19: CARBONYL COMPOUNDS III
CHAPTER 19: CARBONYL COMPOUNDS III A hydrogen bonded to a carbon adjacent to a carbonyl carbon is sufficiently acidic to be removed by a strong base. The carbon adjacent to a carbonyl carbon is called
More informationHydrogen iodide is a strong acid and will drive the reverse reaction, meaning the forward reaction will not occur.
EM 261 Oct 18, 2018 Photosynthesis and Related Reactions O 2 2 O 6 12 O 6 2 O N 3, S, Fe, u, o, other Natural Products D-Glucose R O R OR Ionic substitution S N 1 & R X X 2 hv Petroleum/ Alkanes R N 2
More informationGOLD: A CATALYST WORTH ITS WEIGHT. Reported by Joseph S. Bair 18 October 2007
GLD: A CATALYST WT ITS WEIGT eported by Joseph S. Bair 18 ctober 2007 ITDUCTI ver the last five years homogeneous catalysis by gold complexes has gone from a relatively obscure sampling of reactions to
More informationUse of Cp 2 TiCl in Synthesis
Use of 2 TiCl in Synthesis eagent Control of adical eactions Jeff Kallemeyn May 21, 2002 eactions of 2 TiCl 1. Pinacol Coupling H H H 2. Epoxide pening H H E H Chemoselectivity Activated aldehydes (aromatic,
More informationThe Mechanistic Studies of the Wacker Oxidation. Tyler W. Wilson SED Group Meeting
The Mechanistic Studies of the Wacker xidation Tyler W. Wilson SE Group Meeting 11.27.2007 Introduction xidation of ethene by (II) chloride solutions (Phillips, 1894) -First used as a test for alkenes
More informationBrønsted Acid Proton donor Base Proton acceptor O CH 3 COH + H H 3 O + + CH 3 CO -
hap 7. Acid and Bases Brønsted Acid Proton donor Base Proton acceptor 3 3 3-2 acid base conj. acid conj. base 3 2 S 4 3 - S 4 base acid conj. acid conj. base 6 5 N 2 N 2 6 5 N - N 3 acid base conj. base
More informationOrganic Chemistry Laboratory Summer Lecture 6 Transition metal organometallic chemistry and catalysis July
344 Organic Chemistry Laboratory Summer 2013 Lecture 6 Transition metal organometallic chemistry and catalysis July 30 2013 Summary of Grignard lecture Organometallic chemistry - the chemistry of compounds
More informationThe aldol reaction with metal enolates proceeds by a chair-like, pericyclic process: favored. disfavored. favored. disfavored
The aldol reaction with metal enolates proceeds by a chair-like, pericyclic process: Z-enolates: M 2 M 2 syn 2 C 2 favored 2 M 2 anti disfavored E-enolates: M 2 2 C 3 C 3 C 2 favored 2 M M disfavored In
More informationChapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy
Chapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double (e.g.
More informationTopic 9. Aldehydes & Ketones
Chemistry 2213a Fall 2012 Western University Topic 9. Aldehydes & Ketones A. Structure and Nomenclature The carbonyl group is present in aldehydes and ketones and is the most important group in bio-organic
More information( ) Thermodynamic selectivity (reversible reactions)
II. Reactivity A) General Principles Fundamental Equations G o Ea / RT = "RT ln K eq k = Ae 1) Kinetics vs Thermodynamics Kinetic selectivity (irreversible reactions) [ P 1 ] [ ] = ln k 1 P 2 ( ) = " #G
More informationWilkinson s other (ruthenium) catalyst
Wilkinson s other (ruthenium) catalyst Cl 3 ; 2 h 3, reflux 3h h 3 Cl h 3 h Cl 3 Good catalyst especially for 2 1-alkenes 2, base toluene Cl h 3 h 3 h 3 Et 3 Cl h 3 Cl h 3 h 3 R h 3 h 3 Cl h 3 R RC 2 C
More information