Cationic Olefin Polyannulations: History and Application to Steroid and Other Fused. Polycycle Syntheses
|
|
|
- Randell Willis
- 5 years ago
- Views:
Transcription
1 Enz-A Cationic lefin Polyannulations: istory and Application to Steroid and ther Fused Polycycle Syntheses Cl N David A. Nicewicz
2 Squalene Enzymatic Cyclizations hopene squalene cyclases diplopterol squalene tetrahymanol
3 xidosqualene Enzymatic Cyclizations lanosterol oxidosqualene cyclases cycloartenol 2,3-oxidosqualene ß-amyrin
4 chanism for Squalene Enzymatic Cyclization squalene squalenehopene cyclase Enz-A non-sterol folding hopene diplopterol
5 chanism for xidosqualene Enzymatic Cyclization 2,3-oxidosqualene oxidosqualenelanosterol cyclase Enz-A sterol folding lanosterol protolanoserol cation
6 Acid-Catalyzed Cyclization of 1,5-Dienes & 5 membered rings R + R = ; 6 & 5 membered ring adducts R = ; 6 membered ring only J. W. Cook and C. L. ewett, J. Chem. Soc., 1934, 365. P. G. Stevens and S. C. Spalding, Jr., J. Am. Chem. Soc., 1949, 71, 1687.
7 Stork-Eschenmoser Postulate -Trans olefins lead to trans ring fusions -Cis olefins lead to cis ring fusions Stork G.; Burgstahler, A. W., J. Am. Chem. Soc., 1955, 77, Stadler, P. A.; Eschenmoser, A.; Schinz,.; Stork, G., elv. Chim. Acta, 1957, 40, 2191.
8 Farnesic Acid Cyclizations C 2 + C 2 C 2 C 2 + Stork G.; Burgstahler, A. W., J. Am. Chem. Soc., 1955, 77, Stadler, P. A.; Eschenmoser, A.; Schinz,.; Stork, G., elv. Chim. Acta, 1957, 40, 2191.
9 Farnesylacetic Acid and Monocyclofarnesylacetic Acid Cyclizations C 2 SnCl 4 or SnBr 4 SnCl 4 C 2 C 2 SnCl 4 Stork G.; Burgstahler, A. W., J. Am. Chem. Soc., 1955, 77, 5068.
10 Annulation of Decadienyl Nosylates C S 2 PhN 2 12% 35% C S 2 PhN 2 16% 38% First supporting evidence for Stork-Eschenmoser postulate Johnson, W. S.; Bailey, D. M.; wyang, R.; Bell, R. A.; Jacques, B.; Crandall, J. K., J. Am. Chem. Soc., 1964, 86, 1959.
11 First Biomimetic lefin Polycyclization in Steroid Synthesis dl-16,17-dehydroprogesterone + Johnson, W. S.; Semmelhack, M. F.; Sultanbawa, M. U. S.; Dolak, L. A., J. Am. Chem. Soc., 1968, 90, 2994.
12 First Biomimetic lefin Polycyclization in Steroid Synthesis SnCl 4 EtN 2-80 o C 66% + 7% isomers 3 dl-16,17-dehydroprogesterone Cl Ac C W. S. Johnson, M. F. Semmelhack, M. U. S. Sultanbawa, L. A. Dolak, J. Am. Chem. Soc., 1968, 90, W. S. Johnson, T. t. Li, C. A. arbert, W. R. Bartlett, T. R. errin, B. Staskun, D.. Rich, J. Am. Chem. Soc., 1970, 92, 4461.
13 Aromatic Polyolefin Cyclization SnCl o C Br, K 59% + 12% o-isomer BF 3 Et 2 5:1 mixture of diastereomers estrone Bartlett, P. A.; Johnson, W. S., J. Am. Chem. Soc., 1973, 95, 7501.
14 Acylimmonium Polycyclizations R N n + + R + N n R N n X -X m m m
15 Acylimmonium Polycyclizations N Et C 2 r.t.; 18 h N 100% N Et C 2 r.t.; 18 h N 100% Dijkink, J.; Speckamp, W. N., Tet. Lett., 1977, 11, 935.
16 Acylimmonium Polycyclizations N N Et C 2 r.t.; 18 h 100% N Et C 2 r.t.; 18 h N 60% Dijkink, J.; Speckamp, W. N., Tet. Lett., 1977, 11, 935.
17 Acylimmonium Polycyclizations Used in Azasteroid Synthesis Cl Cl N 1.1 eq (C 2 ) n Et C 2, 25 o C 30% Cl N 13-azaandrosta-1,4-diene-3,17-dione Romero, A. G.; Leiby; Mizsak, S. A., J. rg. Chem., 1996, 61, 6974.
18 Johnson Model for 2,3 xidosqualene Cyclases B- protolanoserol cation B- dammarenyl cation = site of negative point charge Johnson, W. S.; Lindell, S. D.; Steele, J., J. Am. Chem. Soc., 1987, 109, 5852.
19 Cation-Stabilizing Auxiliaries L.A.
20 Cation Stabilizing Auxiliaries: Isobutenyl SnCl 4 0 o C 48% 19% 77% Combined Yield of Tetracyclic Products Johnson, W. S.; Telfer, S. J.; Cheng, S.; Schubert, U., J. Am. Chem. Soc., 1987, 109, % SnCl 4 0 o C 30% Combined Yield of Tetracyclic Products Johnson, W. S.; Wiedhaup, K.; Brady, S. F.; lson, G. L., J. Am. Chem. Soc., 1968, 90, 5277.
21 Cation-Stabilizing Auxiliaries: Fluoride F SnCl 4 0 o C 86% Combined Yield of Tetracyclic Products; No Fluoride-Containing Compounds Major Component Johnson, W. S.; Chenera, B.; Tham, F. S.; Kullnig, R. K., J. Am. Chem. Soc., 1993, 115, 493.
22 Cation-Stabilizing Auxiliaries: Fluoride Si 3 F F SnCl 4-90 o C Major Product: 32% 69% Yield of All Tetracyclic Compounds Johnson, W. S.; Fletcher, V. R.; Chenera, B.; Bartlett, W. R.; Tham, F. S.; Kullnig, R. K., J. Am. Chem. Soc., 1993, 115, 497.
23 Defluoronation Using hsawa-ishi Reagent F Na/K alloy crown ether C 7 8 4ß-hydroxyandrosta-17-one 91% Johnson, W. S.; Fletcher, V. R.; Chenera, B.; Bartlett, W. R.; Tham, F. S.; Kullnig, R. K., J. Am. Chem. Soc., 1993, 115, 497.
24 Retrosynthesis of ß-Amyrin F ß-amyrin F Si 3 Johnson, W. S.; Plummer, M.S.; Reddy, S. P.; Bartlett, W. R., J. Am. Chem. Soc., 1993, 115, 515.
25 Synthesis of ß-Amyrin F Si 3 F 3 CC 2-70 o C F 65-70% F Si 3 F 3 CC 2-78 o C F 60% F ß-amyrin verall Yield: 0.2% Johnson, W. S.; Plummer, M.S.; Reddy, S. P.; Bartlett, W. R., J. Am. Chem. Soc., 1993, 115, 515.
26 Cation Stabilizing Auxiliaries: ß-Silyl Y X nagilactone F X = Si 3, Y = (E-isomer) X =, Y = Si 3 (Z-isomer) Burke, S. D.; Kort, M. E.; Strickland, S. M. S.; rgan,. M., Silks, III, L. A., Tet. Lett., 1994, 10, 1503.
27 Cation Stabilizing Auxiliaries: ß-Silyl Y X TiCl 4, Ti( i Pr) 4 C 2 Cl 2, -78 o C + L.A. + Y X (for E-isomer, 30-40%; for Z-isomer, 85-90%) X = Si 3, Y = (E-isomer) X =, Y = Si 3 (Z-isomer) nagilactone F Burke, S. D.; Kort, M. E.; Strickland, S. M. S.; rgan,. M., Silks, III, L. A., Tet. Lett., 1994, 10, 1503.
28 Concerted vs. Stepwise Cyclization + +? o = - 20 kcal/mol?s o = - 21 eu (-6.25 kcal/mol at 298 K)?G o = - 14 kcal/mol at 298 K Bartlett, P. A., In Asymmetric Synthesis.; Morrison, J. D., Ed; Academic Press: New York, 1984, Vol. 3, pp
29 Concerted vs. Stepwise Cyclization + p-complex + X + Sutherland, J. K., In Comprehensive rganic Synthesis; Trost, B. M., Fleming, I., Eds.;Permagon Press: xford, 1991; Vol. 3, p.341. Bartlett, P. A., In Asymmetric Synthesis.; Morrison, J. D., Ed; Academic Press: New York, 1984, Vol. 3, pp
30 Mimic of Chair-Boat-Chair xidosqualene Enzymatic Cyclization Enz-A protolanoserol cation -Enzymatic cyclization to the protolanolsterol cation has never been emulated in a non-enzymatic system -Chair-boat-chair transition state several kcal/mol less stable than all chair conformation
31 Mimic of Chair-Boat-Chair xidosqualene Enzymatic Cyclization TIPS TIPS Ph 3 P F 3 C 2 C C 2 CF 3 1:1 mixture of E and Z isomers AlCl 2 C 2 Cl 2-95 o C C 2 CF 3 40% Wood, Jr.,. B.; Corey, E. J., J. Am. Chem. Soc., 1996, 118,
32 Mimic of Chair-Boat-Chair xidosqualene Enzymatic Cyclization Wood, Jr.,. B.; Corey, E. J., J. Am. Chem. Soc., 1996, 118,
33 Mimic of Chair-Boat-Chair xidosqualene Enzymatic Cyclization TIPS + + C2 CF 3 TIPS + + C2 CF 3 Wood, Jr.,. B.; Corey, E. J., J. Am. Chem. Soc., 1996, 118,
34 Mimic of Chair-Boat-Chair xidosqualene Enzymatic Cyclization TIPS TIPS AlCl 2 + C 2 CF 3 C 2 Cl 2-95 o C C2 CF 3 TIPS + C2 CF 3 C 2 CF 3 Wood, Jr.,. B.; Corey, E. J., J. Am. Chem. Soc., 1996, 118,
35 Mimic of Sterol Folding in nocerin Synthesis TMS (+)-onocerin TMS Ac TBS farnesyl acetate Yuan, M.; Schreiber, J. V.; Corey, E. J., J. Am. Chem. Soc., 2002, 124,
36 Mimic of Sterol Folding in nocerin Synthesis TBS Li Et 2, -78 o C Li TBS 0.5 eq I 2 74% TBS TBS CsF, PhNTf 2 DME, 23 o C 72% TMS TMSC 2 ZnBr Tf TMS Pd(PPh 3 ) 4 23 o C, 92% Tf Yuan, M.; Schreiber, J. V.; Corey, E. J., J. Am. Chem. Soc., 2002, 124,
37 Mimic of Sterol Folding in nocerin Synthesis TMS TMS 1. AlCl 2 C 2 Cl 2-94 o C 2. TBAF + (+)-onocerin 63% 9% TMS TMS 1. AlCl 2 C 2 Cl 2-94 o C 2. TBAF + 44% (+)-onocerin 19% Yuan, M.; Schreiber, J. V.; Corey, E. J., J. Am. Chem. Soc., 2002, 124,
38 Nazarov-Initiated Polyannulation L.A. + L.A. - + R n 4p conrotatory electrocyclization R n R n
39 Nazarov-Initiated Polyannulation R 3 R 2 R 4 R 1 n BF 3 Et 2, C 2 Cl 2-78 o C-r.t; 2 R 3 R 4 2 R R 1 n 3 C Et 75% 89% 73% 62% 42% Bender, J. A.; Blize, A. E.; Browder, C. C.; Giese, S.; West, F. G., J. Am. Chem. Soc., 1998, 63, 2430.
40 Nazarov-Initiated Polyannulation R 3 R 2 R 4 R 1 n BF 3 - BF + 3 R 3 R 2 R 4 R 1 n R 3 - BF 3 + R 4 R 1 R 2 n R 3 R 1R4 - BF + 3 n R 2 R 3 - F 3 B + R 4 2 R R 1 n R 3 R 4 2 R R 1 n 3 + R 3 R 4 2 R R 1 n Bender, J. A.; Blize, A. E.; Browder, C. C.; Giese, S.; West, F. G., J. Am. Chem. Soc., 1998, 63, 2430.
41 Nazarov-Initiated Polyannulation Ts C 2 Cl 2 0 o C 52% Ph 2 C 2 C + Ph 2 C 2 C BF 3 Et 2 C 2 Cl 2 0 o C 72% + - BF 3 Ph Ph Bender, J. A.; Arif, A. M.; West, F. G., J. Am. Chem. Soc., 1999, 121, 7443.
42 Nazarov-Initiated Polyannulation R 2 R 1 TiCl 4 C 2 Cl 2-78 o C R 2 R 1 Et 99% 73% 98% 74% Bender, J. A.; Arif, A. M.; West, F. G., J. Am. Chem. Soc., 1999, 121, 7443.
43 Conclusions - Cationic olefin polyannulations are efficient methods for the stereoselective generation of fused ring systems. (+)-onocerin ß-amyrin - Stork-Eschenmoser postulate is valid for most systems.
44 Conclusions - Cation-stabilizing auxiliaries can enhance cyclization yields. F Si 3 F 3 CC 2-70 o C F 65-70% - Cyclizations can be initiated by a number of different transient cations. N Et C 2 r.t.; 18 h N 100% R 2 R 1 TiCl 4 C 2 Cl 2-78 o C R 2 R 1 - Cationic olefin polyannulations can be stepwise and concerted, although concerted pathway is not plausible past second ring formation.
45 Acknowledgements - Dr. Jeff Johnson - Johnson Group - UNC-C
[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
![[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](/thumbs/94/119475672.jpg "[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
Non-Enzymatic Enantioselective Polyene Cyclizations. Adam Hill Chem 535 May, 2 nd 2013
Non-Enzymatic Enantioselective Polyene Cyclizations Adam Hill Chem 535 May, 2 nd 2013 Enantioselective Polyene Cyclization (?) General Method to Rapidly Build Molecular Complexity (+) Exquisite Stereo-
Advanced 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
Electrophilic 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)
Stereoselective Organic Synthesis
Stereoselective rganic Synthesis Prabhat Arya Professor and Leader, Chemical Biology Program Dean, Academic Affairs, Institute of Life Sciences (An Associate Institute of University of yderabad Supported
Pericyclic Reactions - Continued
Dr. P. Wipf Page 1 of 7 10/21/2009 Pericyclic eactions - Continued Sigmatropic earrangements Definition: A sigmatropic rearrangement is defined as an intramolecular rearrangement of a σ bond, adjacent
Huang, C.; Gevorgyan, V. J. Am. Chem. Soc. 2009, 131, Daniel Tzvi Cohen Short Literature Feb. 23, MeO HO OH. COOH ( )-Plicatic Acid OH OH
Asymmetric Total Synthesis of ( )-Plicatic Acid via a Highly Enantioselective and Diastereoselective Nucleophilic Epoxidation of Acyclic Trisubstituted lefins H H H H CH ( )-Plicatic Acid H H Sun, B.F.;
Reporter: Yue Ji. Date: 2016/12/26
Literature Report (11) Total Synthesis of Rubriflordilactone B Reporter: Yue Ji Checker: Mu-Wang Chen Date: 2016/12/26 Yang, P.; Yao, M.; Li, J.; Li, Y.; Li, A.* Angew. Chem. Int. Ed. 2016, 55, 6964. Laboratory
Strained 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
Total Synthesis of the Sesquiterpenoid Periconianone A Based on a Postulated Biogenesis
Total Synthesis of the Sesquiterpenoid Periconianone A Based on a Postulated Biogenesis C 3 C3 Liffert, R., Linden, A., Gademann, K. J. Am. Chem. Soc. 2017, 139, 16096 Presented by: Brendyn Smith CEM 852
A Tandem Semipinacol Rearrangement/Alkylation of a-epoxy Alcohols: An Efficient and Stereoselective Approach to Multifunctional 1,3-Diols
A Tandem Semipinacol Rearrangement/Alkylation of a-epoxy Alcohols: An Efficient and Stereoselective Approach to Multifunctional 1,3-Diols B() 2 H H B() 2 H H Hu, X.-D.; Fan, C.-A.; Zhang, F.-M.; Tu, Y.
Carbonyl Ylide Cycloadditions
Carbonyl Ylide Cycloadditions cond. icholas Anderson Denmark Group eting 07/13/10 Carbonyl Ylides Uncharged 1,3-Dipole Conjugated π-system ighly reactive on-isolable Generate in-situ Carbonyl Ylide Stability
Diels-Alder Reaction
Diels-Alder Reaction Method for synthesis of 6-membered ring ne-step, concerted reaction Termed [4+2] cycloaddition reaction where 4 and 2 electrons react. + Diels-Alder Reaction Discovered by. Diels and
I. Introduction. Peng Zhao. Liu lab
Asymmetric Total Synthesis of Mycoleptodiscin A Shupeng Zhou, Hao Chen, Yijie Luo, Wenhao Zhang and Ang Li Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai
Shi 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,
Additions 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
Total Synthesis of Oxazolomycin A
Total Synthesis of xazolomycin A Me xazolomycin A Me Eto, K.; Yoshino, M.; Takahashi K.; Ishihara, J.; atakeyama S. rg. Lett. 2011, 13, 5398 Dimas Paz Wipf group- Current Literature ctober 8, 2011 Dimas
Suggested solutions for Chapter 41
s for Chapter 41 41 PBLEM 1 Explain how this synthesis of amino acids, starting with natural proline, works. Explain the stereoselectivity of each step after the first. C 2 C 2 3 CF 3 C 2 2 Pd 2 C 2 +
Ynolate Chemistry. Jeff Kallemeyn October 22, 2002
Ynolate Chemistry While enolates have numbered among the most important reagents of organic chemistry for more than a century, ynolates have hitherto remained unknown although their chemistry should be
Synthesis of the Stenine Ring System from Pyrrole
Current Literature Presentation gor psenica 06/18/2011 Synthesis of the Stenine Ring System from Pyrrole Bates, R. W.; Sridhar, S. J. rg. Chem., 2011, 76, 5026 5035 gor psenica @ Wipf Group Page 1 of 16
Stereoselective reactions of enolates: auxiliaries
1 Stereoselective reactions of enolates: auxiliaries Chiral auxiliaries are frequently used to allow diastereoselective enolate reactions Possibly the most extensively studied are the Evan s oxazolidinones
Chapter 6 Cycloadditions and Rearrangements 1. Diels-Alder Reactions 2. [2 + 2] Cycloadditions 3. 1,3-Dipolar Additions 4. Cheletropic Reactions 5.
![Chapter 6 Cycloadditions and Rearrangements 1. Diels-Alder Reactions 2. [2 + 2] Cycloadditions 3. 1,3-Dipolar Additions 4. Cheletropic Reactions 5.](/thumbs/89/98941767.jpg "Chapter 6 Cycloadditions and Rearrangements 1. Diels-Alder Reactions 2. [2 + 2] Cycloadditions 3. 1,3-Dipolar Additions 4. Cheletropic Reactions 5.")
Chapter 6 Cycloadditions and earrangements 1. Diels-Alder eactions 2. [2 2] Cycloadditions 3. 1,3-Dipolar Additions 4. Cheletropic eactions 5. Sigmatropic earrangements 1 Diels Alder eactions s-cis 6e-intermediate
Midterm Exam #1 /310 CHEM 6352 Fall 2012
Midterm Exam #1 /310 CEM 6352 Fall 2012 ( %) Name ct 5 th, 2012 18:30-21:00 You may NT use any references or aids to complete the following with the exception of a chemical model set and the scrap paper
Recent 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
Recent Developments of the Nazarov Reaction. Banibrata Ghosh Michigan State University January 14, 2004
ecent Developments of the azarov eaction Banibrata Ghosh Michigan State University January 14, 2004 utline Directed azarov reactions Asymmetric azarov reactions ther recent variants of the azarov reaction
Lecture 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
CHEMISTRY 332 SUMMER 08 EXAM I June 26-28, 2008
First Three Letters of Last Name NAME Network ID CHEMISTRY 332 SUMMER 08 EXAM I June 26-28, 2008 The following materials are permissible during the exam: molecular model kits, course notes (printed, electronic,
Total Synthesis of (+)-Sieboldine A J. Am. Chem. Soc. 2010, 132,
Total Synthesis of (+)-Sieboldine A J. Am. Chem. Soc. 2010, 132, 7876 7877. Current Literature Presentation 10JUL2010 Michael Yang Mike Yang @ Wipf Group Page 1 of 15 7/10/2010 Sieboldine A Background
Initials: 1. Chem 633: Advanced Organic Chemistry 2011 Final Exam
Initials: 1 ame: Chem 633: Advanced rganic Chemistry 2011 Final Exam Please answer the following questions clearly and concisely. In general, use pictures and less than 10 words in your answers. Write
Problem Session(5) Please provide each reaction mechanisms and explain the stereoselectivities.
Problem ession(5) Please provide each reaction mechanisms and explain the stereoselectivities. 2017.10.28. iroaki Matoba Boc 1.BF 3 Et 2,C 2 Cl 2,-78 C; allyltm,-78to-20 C 2.MsCl,Et 3,C 2 Cl 2,0 Ctort
Use 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,
Lewis 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
Nine-Step Enantioselective Total Synthesis of (+)-Minfiensine
ine-step nantioselective Total Synthesis of (+)-Minfiensine Jones, S. B.; Simmons, B.; MacMillan, D. W. C.* J. Am. Chem. Soc. 2009, ASAP. DI: 10.1021/ja906472m Kara George Wipf Group - Current Literature
Stereoselective Organic Synthesis
Stereoselective rganic Synthesis Prabhat Arya Professor and Leader, Chemical Biology Program Dean, Academic Affairs, Institute of Life Sciences (An Associate Institute of University of yderabad Supported
Ladderanes: Uses and Synthesis. Nicholas Anderson Denmark Group Meeting October 28, 2008
Ladderanes: Uses and Synthesis icholas Anderson Denmark Group Meeting ctober 28, 2008 utline Ladderane types and classifications Potential applications of ladderanes Synthesis of ladderanes Ladderane natural
CHAPTER The calculations are shown for each molecule using values from Table 1.5 in Chapter 1. K eq = B A = B 1-B
Chapter CPTER. The calculations are shown for each molecule using values from Table.5 in Chapter. 2 C N 2 C 2 N 2 C C-C N 2 C C 2 C C C (a) = CR2 + C = 2. + 0.2 = 2. kcal mol - If + = = NR + G C + G CR2
The Vetivane Sesquiterpenes
Group eting In 1940, Pfau and Plattner proposed structures for b-vetivone, one of the constituents of vetiver oil, an aromatic oil from vetiver grass. The structure was assigned based on extensive degradative
TMSCl 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.
Methods to Spiroketals: Classic and Modern Approaches
thods to Spiroketals: Classic and Modern Approaches 2 C kadaic Acid Problem Set September 3, 2010 12:00pm, 3005 Malott Significance of Spiroketals in Nature Ac 12 Cl Ac Spongistatin 1 isolated from Spongia
Suggested solutions for Chapter 32
s for Chapter 32 32 PBLEM 1 Explain how the stereo- and regio- chemistry of these reactions are controlled. Why is the epoxidation only moderately diastereoselective, and why does the amine attack where
Synthetic Efforts Towards Anthracyclines Using the Asymmetric Diels-Alder Reaction
1 Synthetic Efforts Towards Anthracyclines Using the Asymmetric Diels-Alder Reaction D C B A Me Me N 2 Figure 1: Doxorubicin (DX) 1. Introduction Doxorubicin (1) is an effective drug used in chemotherapy,
Rhodium Catalyzed Alkyl C-H Insertion Reactions
Rhodium Catalyzed Alkyl C-H Insertion Reactions Rh Rh Jeff Kallemeyn 5/17/05 1. Cyclopropanation The Versatile and Reactive Rhodium Carbene R + Et Rh 2 (Ac) 4 R C 2 Et N 2 2. [2,3] sigmatropic rearrangement
Domino Reactions in Total Synthesis! Reporter: Tianhe Yang! Supervisors: Prof. Yang! Prof. Chen! Prof. Tang!
1! Domino Reactions in Total Synthesis! Reporter: Tianhe Yang! Supervisors: Prof. Yang! Prof. Chen! Prof. Tang! 2! utline! 1. Brief Introduction! 2. ucleophilic Dominoes! 3. Electrophilc Dominoes! 4. Radical
CHEM 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
Comparative Synthesis of Ingenol. Tyler W. Wilson SED Group Meeting
Comparative Synthesis of Ingenol Tyler W. Wilson SED Group eting 2.27.07 Ingenol: Biology, Isolation, and istory During WWII a latex was manufactured by precipitating the milky juice of the Euphorbia Ingen
Total Synthesis of (+)-Suaveolindole
1 Total Synthesis of (+)-Suaveolindole 15 2 C 16 11 Emile J. Velthuisen and Samuel J. Danishefsky J. Am. Chem. Soc. 2007, 9, 10640-10641 Julia Vargas September 15, 2007 2 utline Isolation and Elucidation
Pericyclic Reactions 6 Lectures Year 3 Handout 2 Michaelmas 2017
Pericyclic eactions 6 Lectures Year 3 andout 2 Michaelmas 27 π6 a σ2 s Prof Martin Smith CL 3.87 martin.smith@chem.ox.ac.uk http://msmith.chem.ox.ac.uk/ Cycloadditions: oxyallyl cation P46 ω s σ2 s odd
4.MeOTf,DCM,76% 5.1-B,MeCN,50 C,89% 6.Oxone,MeCN/H 2 O,0 C,67% 7.PIFA,DCM,rt; TFA/H 2 O(3/1),55 C,26%
Problem Session 1 Please fill in the blank and provide each reaction mechanisms. 2018. 1. 11. Akira Tomiyama 1 1-1 1.1-A,i-Pr 2 Et(excess),DCM,-78 C; then1-1,dcm,-78 C,57% 2. 2,aneyi,;DMP,DCM,69% 3.TMSTf,Et
Zr-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
Lecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions
Lecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions I. Reaction of Enols & Enolates with ther Carbonyls Enols and enolates are electron rich nucleophiles that react with a number
A Concise Synthesis of ( )- Aplyviolene Facilitated by a Stragetegic Ter<ary Radical Conjugate Addi<on
A Concise Synthesis of ( )- Aplyviolene Facilitated by a Stragetegic Ter
Ethers. Chapter 14: Ethers, Epoxides, & Sulfides. General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:
Chamras Chemistry 106 Lecture Notes Examination 1 Materials Chapter 14: Ethers, Epoxides, & Sulfides Ethers General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:
Asymmetric Radical Reactions. Zhen Liu 08/30/2018
Asymmetric adical eactions Zhen Liu 08/30/2018 Contents Introduction eactions Using Chiral Auxiliary Chiral Lewis Acid-diated eactions Transition tal-catalyzed eactions eactions Using Chiral rganocatalysts
Problem session (3) Daiki Kuwana. Please fill in the blank and explain reaction mechanisms and stereoselectivities.
Problem session (3) Daiki Kuwana Please fill in the blank and explain reaction mechanisms and stereoselectivities. 1. 1-1 1. (Ac) 2 (10 mol%), DPEphos (20 mol%) Et 3, toluene, 90 C 2. s 4 (14 mol%), M;
Literature Report. A 11-Steps Total Synthesis of Magellanine through a Gold(І)-Catalyzed Dehydro Diels-Alder Reaction
Literature Report 11-Steps Total Synthesis of Magellanine through a Gold(І)-Catalyzed ehydro iels-lder Reaction Reporter: ong-qiang Shen Checker: Cong Liu ate: 2017/06/19 McGee, P.; Bétournay, G.; Barabé,
Lewis 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
Catalytic Asymmetric Intramolecular. Reactions
Catalytic Asymmetric Intramolecular Pauson-Khand and Pauson-Khand-Type eactions Steven Ballmer CEM 535 Seminar ctober 9, 2008 University of Illinois at Urbana-Champaign pyright 2008 by Steven Ballmer Synthetic
Short Literature Presentation 10/4/2010 Erika A. Crane
Copper-Catalyzed Enantioselective Synthesis of trans-1- Alkyl-2-substituted Cyclopropanes via Tandem Conjugate Additions-Intramolecular Enolate Trapping artog, T. D.; Rudolph, A.; Macia B.; Minnaard, A.
O + 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,
Total synthesis of Spongistatin
Literature Semminar 1. Introduction: Total synthesis of Spongistatin Chen Zhihua (M2) Isolation: Pettit et al. J. rg. Chem. 1993, 58, 1302. Kitagawa et al. Tetrahedron Lett. 1993, 34, 1993. Fusetani et
Tandem Use of Cobalt-Mediated Reactions to Synthesize (+)-Epoxydictymene, a Diterpene Containing a Trans-Fused 5-5 Ring System
Tandem Use of balt-diated eactions to Synthesize (+)-Epoxydictymene, a iterpene ntaining a Trans-Fused 5-5 ing System (+)-Epoxydictymene Schreiber, S. L.; et al. J. m. hem. Soc. 1997, 119, 4353. Problem
Prof. Ang Li. Literature Seminar Kosuke Minagawa (D2)
Prof. Ang Li Literature Seminar 2017. 10. 28 Kosuke Minagawa (D2) 1 2 3 aspidodasycarpine 1) 2 C sespenine 3) atural Products Synthesized by Ang Li group clostrubin 6) drimentine A 7) i-bu rubriflordilactone
Chiral 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
Silacyclopropanes Anne-Marie D echert Dechert June 25, 2008
lacyclopropanes Anne-Marie Dechert June 25, 2008 utline istory Synthesis eactions of lacyclopropanes Applications to Synthesis Summary/Conclusion Prior Attempts oberts, J.; Dev, S. J. Am. Chem. Soc. 1951,
2.339 Practice Problems
2.339 Practice Problems Basics of Structure and Mechanism 1. What is the expected site of protonation in an enol ether (C=C)? Justify your choice using resonance structures. 2. ank the following molecules
A 1,3 Strain and the Anomeric Effect. Michael Shaghafi Chem. Topics Feb. 6, 2012
A 1,3 Strain and the Anomeric Effect Michael Shaghafi Chem. Topics Feb. 6, 2012 Introduction: Definition of A 1,3 Strain m L L m m 3 L 3 1 1 otation about σ-bond between α-stereocenter and olefin is associated
Highlights in the Progress of Biomimetic Strategies for the Construction of Complex Natural Products. Chris Galliford 26 th August 2003
ighlights in the Progress of Biomimetic Strategies for the Construction of Complex Natural Products Chris Galliford 26 th August 2003 The Biomimetic Approach Inspiration for biomimetic synthesis of a target
Catalytic Asymmetric Acyl Halide-Aldehyde Cyclocondensation Reactions of Substituted Ketenes
Catalytic Asymmetric Acyl Halide-Aldehyde Cyclocondensation eactions of Substituted Ketenes Scott G. elson, Cheng Zhu, and Xiaoqiang Shen J. Am. Chem Soc. 2004, 126, 14-15. Michael C. Myers, Literature
STEREOELECTRONIC EFFECTS (S.E.) IN ORGANIC CHEMISTRY
STEREOELECTRONIC EFFECTS (S.E.) IN ORGANIC CHEMISTRY Pierre Deslongchamps (version du 16 février 2010) Cf. pour le livre: http://pages.usherbrooke.ca/pdeslongchamps/cv.htm 1 SECTION 8 Stereoelectronic
Organic Tutorials 3 rd Year Michaelmas Transition Metals in Organic Synthesis: (General paper level) ! 1! Reading
rganic Tutorials 3 rd Year Michaelmas 2010 Transition Metals in rganic Synthesis: (General paper level) Reading 1. Lecture Course, and suggested references from this. 2. Clayden, Greaves, Warren and Wothers.
I. Introduction. II. Retrosynthetic Analysis. Andrew Baggett. Liu lab
Total Synthesis of Limonin Shuji Yamashita,* Akito Naruko, Yuki Nakazawa, Le Zhao, Yujiro Hayashi, Masahiro Hirama Tohoku University, Department of Chemistry, Aramaki-aza aoba, Aoba-ku, Sendai 980-8578
Dual enantioselective control by heterocycles of (S)-indoline derivatives*
Pure Appl. Chem., Vol. 77, No. 12, pp. 2053 2059, 2005. DOI: 10.1351/pac200577122053 2005 IUPAC Dual enantioselective control by heterocycles of (S)-indoline derivatives* Yong Hae Kim, Doo Young Jung,
Problem Set 2: Reactions of Carbocations - KEY
Problem Set 2: eactions of Carbocations - KEY Due Tuesday, 10/11/16 1. a. Formation of 1 and 2 silyl ethers is always high-yielding, but selective silylation of a single hydroxyl group can be challenging.
Syntheses of Leucascandrolide A. Supergroup Meeting August 4 th, 2004 Yu Yuan
Syntheses of Leucascandrolide A Supergroup Meeting August 4 th, 2004 Yu Yuan Leucascandrolide A Me Me Me Dambrosio, M.; Guerriero, A.; Debitus, C.; Pietra, F. elvetica Chimica Acta 1996, 79, 51-60 Me 1
Catalytic 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
Mild 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
SECTION 12. «POT-POURRI» in Organic Synthesis (2018)
SECTIN 12 «PT-PURRI» in rganic Synthesis (2018) 1 Total Synthesis of Erythromycin A via a Spiroketal ERYTRMYCIN A DESLNGCAMPS et al. Can. J. Chem. 1985, 63, 2810-2820. 2 Tetrahydropyran Derivative as Starting
Pericyclic Reactions
Pericyclic eactions Definition: 1. Concerted reaction that proceed via a cyclic transition state 2. No distinct intermediates in the reaction 3. Bond forming and bond breaking steps are simultaneous but
Chapter 5 Three and Four-Membered Ring Systems
Chapter 5 Three and Four-mbered ing ystems 5.1 Aziridines Aziridines are good alkylating agents because of their tendency to undergo ring-opening reaction with nucleophiles 例 mitomycin C antibiotic and
Total Synthesis of Maoecrystal V: Early-Stage of C-H Functionalization and Lactone
Literature Report Total Synthesis of Maoecrystal V: arly-stage of C- Functionalization and Lactone Assembly by Radical Cyclization Reporter: Ji Yue Checker: Chen Muwang Date: 2013/12/02 Zakarian, A. et
Asymmetric 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%
Chiral Diol Promoted Boronates Addi3on Reac3ons. Lu Yan Morken Group Boston College
Chiral Diol Promoted Boronates Addi3on Reac3ons Lu Yan Morken Group Boston College Main Idea R R B or R R B Ar * exchange B * * or B Ar R 1 R 1 R 2 R 1 R 2 Products not nucleophilic enough nucleophilic
JOC Year-in-Review, 1984
Baran Lab Group eting JC Year-in-eview, 198 Y oshihiro Ishihara Statistics for J. rg. Chem. 198, Volume 9, Issues 1-26: 1313 Papers 1 erbert C. Brown 8 Albert Padwa 8 Leo A. Paquette 7 Dale L. Boger 7
Rhenium-Catalyzed Synthesis of Multisubstituted Aromatic Compounds via C-C Single-Bond Cleavage
henium-catalyzed Synthesis of Multisubstituted Aromatic Compounds via C-C Single-Bond Cleavage Kuninobu, Y.; Takata,.; Kawata, A.; Takai, K. rg. Lett. ASAP Et 5 6 cat. [ebr(c) 3 (thf)] 2 5 6 Current Literature
Suggested solutions for Chapter 34
s for Chapter 34 34 PRBLEM 1 Predict the structure of the product of this Diels- Alder reaction. C 2 +? 3 Si Can you deal with a moderately complicated Diels- Alder? The diene is electron- rich and will
Asymmetric Diels Alder Reactions
Asymmetric Diels Alder eactios Chiral Auxiliaries (-)-8-eylmethol favorable!-stackig 3 C 3 C C 3 AlCl 3 3 C 3 C C 3 s-tras Lewis-acid complex AlCl 3 Cl JACS, 1975, 1610 frot-face approach of diee B 3 C
Synthesis of Amphidinolide X and an Exploration of Key Reactions
PJM 1/12/05 Synthesis of Amphidinolide X and an Exploration of Key eactions Lepage,.; Kattnig, E.; Furstner, A. JACS, 2004, 126, 15970-15971. 7 13 1 6 19 - Produced by marine dinoflagellates, Amphidinium
Organic Chemistry I (Chem340), Spring Final Exam
rganic Chemistry I (Chem340), pring 2005 Final Exam This is a closed-book exam. No aid is to be given to or received from another person. Model set and calculator may be used, but cannot be shared. Please
Organic Electron Donors
rganic Electron onors Yang Li Zakarian esearch Group epartment of Chemistry and Biochemistry University of California, anta Barbara 11/15/2018 2 2 2 2 2 2 TAF1 TAE TAF2 TTF BPL utlines rganic Electron
VI. 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.
[3,3]-Sigmatropic rearrangements
![[3,3]-Sigmatropic rearrangements](/thumbs/75/71504906.jpg "[3,3]-Sigmatropic rearrangements")
1 [3,3]-Sigmatropic rearrangements heat R 1 R 3 R 1 R 3 R 1 R 3 A class of pericyclic reactions whose stereochemical outcome is governed by the geometric requirements of the cyclic transition state Reactions
A New Strategy for Efficient Synthesis of Medium and Large Ring Lactones without High Dilution or Slow Addition
A ew Strategy for Efficient Synthesis of Medium and Large ing Lactones without High Dilution or Slow Addition BF 3 Et 2 TIPS 2,4,6-collidine n + n+2 ' ' Zhao, W.; Li, Z; Sun, J. J. Am. Chem. Soc. 2013
Synthesis of 1,3-Diols via Controlled, Radical-Mediated C-H Functionalization
Synthesis of 1,3-Diols via Controlled, Radical-Mediated C- Functionalization Chen, K.; Richter, J. M.; Baran, P. S. J. Amer. Chem. Soc. 2008, 130, 7247-7249. Literature Group Presentation Wynter Gilson
Chemistry 206. Advanced Organic Chemistry. Intramolecular Enone-Olefin Photocycloadditions Directed Toward Natural Product Synthesis
Chemistry 206 Advanced rganic Chemistry andout 36A Intramolecular Enone-lefin Photocycloadditions Directed Toward atural Product Synthesis Travis Dunn Evans Group Seminar, March 31, 2000 DAE Group Friday
Renaud Group Exercise Set
Renaud Group Exercise Set Prepared by ick Tappin 08/07/16 Spectroscopy 1. Deduce the structures for compounds A, B, and C C 6 10 3 A IR: 1745 and 1720 cm -1 13 C-MR: δ 208, 172, 51, 37, 32, and 27 ab 4
Keisuke Suzuki. Baran lab Group Meeting 6/11/16. Shigenobu Umemiya. Akira Suzuki. Takanori Suzuki (Hokkaido University)
197.D., Teruaki Mukaiyama, University of Tokyo 193 Assistant Professor, Keio University 197 Lecturer, Keio University 199 Assocate Professor, Keio University 1990 Visiting Professor, ET 1994 ull Professor,
Strategies for Stereocontrolled Synthesis
Chemistry. Synthetic rganic Chemistry II Lecture 3 March, 2007 Rick L. Danheiser Massachusetts Institute of Technology! Thermodynamic Control Strategies! Kinetic Control Strategies! Strategies for the
Nuggets 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
Scope and Facial Selectivity of the Prins-Pinacol Synthesis of Attached Rings
Scope and Facial Selectivity of the Prins-Pinacol Synthesis of Attached Rings By Larry E. verman and Emile J. Velthuisen Leading Reference J. rg. Chem. 2006, 71, 1581-1587 Presented by Zhenyu Zhong Journal
Stereoselective reactions of enolates
1 Stereoselective reactions of enolates Chiral auxiliaries are frequently used to allow diastereoselective enolate reactions Possibly the most extensively studied are the Evan s oxazolidinones These are