Chemistry 206. Advanced Organic Chemistry. Intramolecular Enone-Olefin Photocycloadditions Directed Toward Natural Product Synthesis
|
|
|
- Laurel Jean Bond
- 6 years ago
- Views:
Transcription
1 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 Afternoon Seminar March 31, 2000 D. A. Evans Monday September 27, A-00-Cover page 2/26/02 6:42 PM
2 Intramolecular Enone-lefin Photocycloadditions Directed Toward atural Product Synthesis Travis Dunn DAE Group Friday Afternoon Seminar March 31, 2000 hν Lead References: Intramolecular Enone-lefin Photocycloaddition Crimmins, M.T. Chem. Rev. 1988, 88, Cycloaddition/Fragmentation Strategies in Synthesis Winkler, J.D., et al. Chem. Rev. 1995, 95, chanism of Enone-lefin Photocycloaddition Schuster, D.I., et al. Chem. Rev. 1993, 93, Introduction and Scope I) chanistic considerations of the enone-olefin photocycloaddition II) Selected synthetic examples: A) The ppolzer syntheses B) The Pattenden syntheses C) The Pirrung syntheses D) ne hit wonders E) The Crimmins syntheses F) The Winkler syntheses The following will not be covered in this seminar: I) on-target motivated studies of the intramolecular photocycloaddition II) Intramolecular Paterno-Büchi reactions III) Intramolecular ketene cycloadditions IV) ther intramolecular photocycloadditions (e.g. arene-olefin meta cycloadditions) 36A-01-andout 3/31/00 1:29 PM
3 chanistic Considerations of the Enone-lefin Photocycloaddition 1 3 Inter- System Crossing Enone 1 Enone 3 Alkene ,4 Biradical 3 Adducts hν Decay? 3? Inter- System Crossing 1 1 Enone Exciplex + 1,4 Biradical 1 Adducts Possibility of alkene isomerization + Reversion to starting materials Product formation Alkene Enone A note on light sources: The source of light is usually a mercury lamp. A filter is usually used to remove light below a certain wavelength. The two most common are Pyrex glass, which allows light with λ > 290 nm to pass, and "uranium" glass, which allows light with λ > 350 nm wavelength to pass. Product Schuster, D.I., et al. Chem. Rev. 1993, 93, 3. This product can also arise via similar intermediates (±) β-bulnesene and Epi-β-bulnesene Ac Prepared in 5 steps and 23% yield from 3-methyl-5-bromo-1-pentene hν, Pyrex, c-ex, rt, 3 h 76% Ac α:β 3.3: 1 1) MgI, Et 2 2) K, dioxane 67% Unknown mixture MsCl, Et 3 Ph 3 P=C 2 72% Grob 67% Ms α: 1-Epi-β-bulnesene β: β-bulnesene Stereochemical rationale (TBD) Ac Ac Major Product 36A-02-andout 3/31/00 1:30 PM ppolzer, W., et al. elv. Chim. Acta., 1980, 63, 1198.
4 (+)-Longifolene and (+)-Sativene C Three steps Bn hν, Pyrex, cyclohexane, C 2 Bn 95% ee 77% rt, 2 h (+)-Sativene Ten steps 18% Six steps 47% 2, Pd/C Ac 96% 85% ee This intermediate could be recrystallized to optical purity in 56% yield. * C 2 Bn 3:2 epimeric mixture at starred carbon (+)-Longifolene ppolzer, W., et al. J. Am. Chem. Soc. 1978, 100, ppolzer, W., et al. elv. Chim. Acta. 1984, 67, (±)-Epiprecapnelladiene Three steps 56% Bz hν, Pyrex hexane, rt, 6 h 98% Bz ne diastereomer Stereochemical rationale (Pattenden) 1) LiMDS, I 2) K, DMS 36% Bz Bz Six steps 28% Irradiation of the enol acetate resulted in a 92:8 mixture, presumably due to the smaller size of the acetate versus benzoate. Epiprecapnelladiene Pattenden, G., et al. J. Chem. Soc., Chem. Comm. 1980, Pattenden, G., et al. J. Chem. Soc., Perkin Trans. I 1983, A-03-andout 3/31/00 1:32 PM
5 (±)-Pentalenene TBS Prepared in eleven steps and 28% yield from 2,2-dimethyl-4-pentenal hν, Pyrex, hexane, rt, 7h 81% TBS "only product" 3 CuLi 2 82% TBS F, 2 TF 73% BF 3 Et 2 C 2 Cl 2 1) Ph 3 P=C 2 2) RhCl % 30% 38% (±) Pentalenene Pattenden, G., et al. Tetrahedron Lett. 1984, 25, Pattenden, G., et al.tetrahedron 1987, 43, (±)-Isocomene hν (350 nm), hexane, rt, 24h 77% ne isomer Three steps 73% Ph 3 P=C 2 77% Et Ts, C % Isocomene 36A-04-andout 3/31/00 1:33 PM Pirrung, M.C. J. Am. Chem. Soc. 1979, 101, Pirrung, M.C. J. Am. Chem. Soc. 1981, 103, 82.
6 (±)-Pentalenolactone G thyl Ester Two steps 46% hν, Pyrex, C 2 Cl 2, rt 70% Mixture of anomers. Four steps 62% Pentalenolactone G thyl Ester C ine steps 2% LiBr, MPA C % ne anomer. Stereochemistry unknown. Pirrung, M.C., et al.tetrahedron Lett. 1986, 27, Pirrung, M.C., et al. J. rg. Chem. 1988, 53, 227. (-)-Paeoniflorin Ten steps 47% C hν (350 nm), hexane, 64% C Bz Twelve steps 10% C R * 1) ab 4 2)Acylation 3)Resolution 47% C (-)-Paeoniflorin atakeyama, S., Takano, S., et al. J. Am. Chem. Soc. 1994, 116, A-05-andout 3/31/00 1:34 PM
7 (±)-Valeranone Ts 61% 1:1 mixture of diastereomers. Separated after photolysis. hν, Pyrex, C/acetone (9:1), 0-15 o C, 10h 98% 1) DIBAL- 2) Ts 50% 7 4:1 mixture Valeranone:7-Epi-valeranone Four steps 74% Seperable mixture α:β 3:2 Takeshita,. et al. Bull. Chem. Soc. Jpn. 1993, 66, Studies toward Cytochalasin C Br Et S 2 Ac Bn Cytochalasin C Seventeen steps 17% xidation state crucial Base S hν (254 nm), C, rt, 40 min 94% S 2 S : A-06-andout 3/31/00 1:35 PM Fuchs, P.L., et al. J. rg Chem. 1982, 47, 3121.
8 (±)-ibiscone C Et Six steps hν, uranium glass, i-pr 60% i-pr hexane, rt, 24h 60% i-pr 1.5 : 1.0 i-pr 3 ; Ph 3 P C i-pr Four steps 7% i-pr Ts, C % i-pr ibiscone C ot isolated Smith, A.B., III, et al. J. Am. Chem. Soc. 1982, 104, Smith, A.B., III, et al. J. Am. Chem. Soc. 1984, 106, Studies toward Perhydrohistrionicotoxin n-c 4 9 n-c 5 11 Perhydrohistrionicotoxin n-c 4 9 Three steps n-c 4 9 hν, uranium glass,,aac n-c4 9 Et 42% rt, 2 d Photoadduct not isolable 1) ab 4 Ac n-c 4 9 Wilkinson's catalyst Ac C n-c 4 9 Ac C n-c 4 9 2) 3 ; Ph 3 P 3) Ac 2, DMAP 9% 17% Smith, A.B., III, et al. J. rg. Chem. 1984, 49, A-07-andout 3/31/00 1:36 PM
9 (±)-irsutene C 6 6 hν, Pyrex, EtAc, 90% rt, 30 min 85% Flash Vacuum Pyrolysis 500 o C "Quantitative" irsutene Seven steps 8% Formal syntheses of capnellene and coriolin were reported using a similar photoaddition/fragmentation reaction. hta, G., et al. J. Am. Chem. Soc. 1986, 108, hta, G., et al. J. Chem. Soc., Chem. Comm. 1981, 756. (±)-Pentalenene, (±)-Pentalenic Acid and (±)-Deoxypentalenic Acid from a Common Precursor. C CEt hν, uranium glass hexane, rt, 36 h 73% 9 C CEt + 1 : 13 C CEt 9 Three steps 44% The stereochemistry at the starred carbon was not determined, but the products were isolated as a mixture. C Stereochemical rationale (Crimmins) C R C-9 dr Et i-pr 13:1 17:1 >20:1 Varying the size of the indicated alkyl group influenced the stereoselectivity CEt CEt CR C Consistent with predominant stereochemistry R at C-9 36A-08-andout 3/31/00 1:37 PM Crimmins, M.T., et al. J. rg. Chem. 1984, 49, Crimmins, M.T., et al. J. Am. Chem. Soc. 1986, 108, 800.
10 (±)-Pentalenene, (±)-Pentalenic Acid and (±)-Deoxypentalenic Acid from a Common Precursor. C CEt + 9 C CEt 9 Li, 3, TF 90% C CEt 1 : 13 Reduction performed on mixture of photoadducts. Diastereomers separated after reduction. Three steps 89% R=, R'=, Pentalenene, nine steps, 27% R=, R'=C, Pentalenic acid, eight steps, 42% R=, R'=C, Deoxypentalenic acid, eleven steps, 22% R R' Steps Crimmins, M.T., et al. J. rg. Chem. 1984, 49, Crimmins, M.T., et al. J. Am. Chem. Soc. 1986, 108, 800. (±)-Silphinene Seven steps 46% hν, uranium glass hexane, rt, 4 h 94% TMSI C reflux 89% Silphinene 1) LDA, TF (Et) 2 PCl 2) Li, 2 63% Bu 3 Sn, C % C 2 I Plus a 14% yield of isosilphinene Crimmins, M.T., et al. J. Am. Chem. Soc. 1986, 108, Crimmins, M.T., et al. Tetrahedron Lett. 1985, 26, A-09-andout 3/31/00 1:38 PM
11 (±)-Laurenene C hν, uranium glass 100 o C, PhCl 87% C * C Prepared in twelve steps and 27% yield from 4,4-Dimethyl-cyclopenteneone 1.5:1 α:β at starred carbon Three steps 89% Eight steps 7% CEt 1) a, 3, Et 2 2) 2, Pd/C 80% * CEt Laurene Crimmins, M.T., et al. J. Am. Chem. Soc. 1987, 109, Crimmins, M.T., et al. Tetrahedron Lett. 1985, 26, 997. (±)-Lubiminol E 1 E For E=, MM2 calculations suggest that 1 should be more stable than 2 by 1.1 kcal/mol. E E C 36A-10-andout 3/31/00 1:39 PM hν 97% C 3 83:17 C 4 Crimmins, M.T., et al. Tetrahedron Lett. 1996, 37, Crimmins, M.T., et al. J. Am. Chem. Soc. 1998, 120, 1747.
12 (±)-Lubiminol E 5 6 E For E=, MM2 calculations suggest that 5 should be more stable than 6 by 1.5 kcal/mol. E E 7 8 C C hν 98% 7 nly isolated product Crimmins, M.T., et al. Tetrahedron Lett. 1996, 37, Crimmins, M.T., et al. J. Am. Chem. Soc. 1998, 120, (±)-Lubiminol Et Five steps 48% C hν, uranium glass hexane/c 2 Cl 2 rt, 15 h 98% C 1) Ts, 2 2) (imid) 2 C=S, DMAP 77% Eleven steps Dowd- C Bu 3 Sn AIB C S Lubiminol C 2 12% C Beckwith α:β 2:3 92% imid 36A-11-andout 3/31/00 1:39 PM Crimmins, M.T., et al. Tetrahedron Lett. 1996, 37, Crimmins, M.T., et al. J. Am. Chem. Soc. 1998, 120, 1747.
13 (±)-Bilobalide TMS Y TMS Y Bilobalide CEt hν, uranium glass hexane/c 2 Cl 2 CEt TMS rt, 6 h 78% TMS one diastereomer CEt hν, uranium glass hexane/c 2 Cl 2 CEt CEt rt, 5 h 100% Crimmins, M.T., et al. J. Am. Chem. Soc. 1992, 114, Crimmins, M.T., et al. J. Am. Chem. Soc. 1993, 115, (±)-Bilobalide TMS TMS CEt Desired 1 EtC CEt EtC CEt TMS CEt TMS TMS Undesired 2 TMS CEt Desired 3 CEt CEt EtC EtC CEt Undesired 4 MM2 calculations suggested that 1 was more favored than 2 by approximately 1.6 kcal/mol, while there was almost no difference in energy between 3 and 4 (0.2 kcal/mol). Crimmins, M.T., et al. J. Am. Chem. Soc. 1992, 114, Crimmins, M.T., et al. J. Am. Chem. Soc. 1993, 115, A-12-andout 3/31/00 1:41 PM
14 (±)-Bilobalide Seven steps Piv hν, uranium glass hexane, rt, 18 h 5% Piv C 20% TMS 80% TMS TMS Piv TMS Piv 25% TMS Piv C Piv 1) Pb(Ac) 4, 2), Ts Piv 50% Piv 92% TMS TMS LDA, MoP 76% Crimmins, M.T., et al. J. Am. Chem. Soc. 1992, 114, Crimmins, M.T., et al. J. Am. Chem. Soc. 1993, 115, (±)-Bilobalide C Piv 1) LiAl 4 2) Pb(Ac) 4 80% m-cpba 94% Jones reagent 1) dimethyldioxirane 2) Jones reagent 81% 99% Bilobalide Crimmins, M.T., et al. J. Am. Chem. Soc. 1992, 114, Crimmins, M.T., et al. J. Am. Chem. Soc. 1993, 115, A-13-andout 3/31/00 1:42 PM
15 (±)-Ginkgolide B Eight steps CEt hν, uranium glass hexane, rt, 18 h CEt EtC 71% TES 100% TES ne isomer Four steps 49% Twelve steps 11% 1) 2, Ts dimethyldioxirane 2), Ts, C() 3 Ginkgolide B 89% Crimmins, M.T. et al. J. Am. Chem. Soc. 1999, 121, Crimmins, M.T. et al. Tetrahedron Lett. 1989, 30, Synthesis of the Core of the Ingenane Diterpenes Three steps 40% C 2 hν, Pyrex Ingenol C, Acetone (9:1) 0 o C, 90 min 83% Stereochemical rationale (Winkler) C K 83% Ingenane Core ne isomer 36A-14-andout 3/31/00 1:44 PM Winkler, J.D., et al. J. Am. Chem. Soc. 1987, 109, 2850.
16 Synthetic Studies Toward the Taxane Core hν, Pyrex C/Acetone (9:1) rt one of the desired photoadduct could be isolated. Ph Bz Taxol Ac Ac hν, Pyrex C/Acetone (9:1) rt, 30 min 75% 1) K, 2) C % E ne isomer E=C Winkler, J.D., et al.tetrahedron Lett. 1986, 27, Winkler, J.D., et al. J. rg. Chem. 1989, 54, Winkler, J.D., et al.tetrahedron 1992, 48, (-)-Perhydrohistrionicotoxin n-c 5 11 Br Derived from glutamic acid Six steps 34% n-c 5 11 hν, Pyrex, C, 0 o C, 30 min 95% 15:1 ratio of epimers at starred carbon. Major isomer shown. Minor isomer epimerizes to major upon chromatography. * 1) ab 4 2) a, TF Stereochemical rationale (Winkler) 63% C 5 11 C 5 11 n-c 5 11 Seven steps 43% n-c 4 9 Perhydrohistrionicotoxin n-c A-15-andout 3/31/00 1:45 PM Winkler, J.D., et al. Tetrahedron Lett. 1986, 27, Winkler, J.D., et al. J. Am.Chem. Soc. 1989, 111, 4852.
17 Formal Synthesis of Vindorosine L-Tryptophan C Cbz Five steps 48% Cbz hν, Pyrex, C, 0 o C, 65 min 91% (R) 3 C Cbz Stereochemical rationale (Winkler) Cbz C(R) 3 Intermediate in Büchi's racemic synthesis >97%ee Ac Büchi Eight steps 3% Et Ac C Vindorosine Eight steps 20% C(R) 3 = (R) 3 C Cbz Winkler, J. D., et al. J. Am. Chem. Soc , Büchi, G., et al. J. Am. Chem. Soc. 1971, 93, ne diastereomer (±)-Manzamine A P R P R Y Y Manzamine A P Y R P Y R P Y R For an analysis of the total synthesis of Manzamine A, see the Evans Group Seminar "Approaches the the Total Synthesis of the Manzamine Alkaloids," emaka Rajapakse, Jan. 21, A-16-andout 3/31/00 1:46 PM Winkler, J.D., et al. Tetrahedron Lett. 1993, 34, Winkler, J.D., et al. Isr. J. Chem. 1997, 37, 47. Winkler, J.D., et al.tetrahedron 1998, 54, Winkler, J.D., et al. J. Am. Chem. Soc. 1998, 120, 6425.
18 (±)-Manzamine A Model system: Saturated ring hν, Pyrex benzene, rt, 90 min 100% Possible solution: Epimerize after cyclization Wrong relative stereochemistry at three new centers. C hν, Pyrex C, rt, 1h C C 25% P Manzamine Core nly isolable product is from photochemical cleavage, rearrangement. Winkler, J.D., et al. Tetrahedron Lett. 1993, 34, Winkler, J.D., et al. Isr. J. Chem. 1997, 37, 47. Winkler, J.D., et al.tetrahedron 1998, 54, Winkler, J.D., et al. J. Am. Chem. Soc. 1998, 120, (±)-Manzamine A Solution to the solution: Mask the ketone as an easily accessible alcohol C Swern C C Readily available by L-Selectride reduction of the ketone 1) hν, Pyrex C, 0 o C, 12 h 2) Et 3 Cl 3) DMAP 41% C Minor dr 2.3:1.0 1 C a 1 Ent-2 Swern P Manzamine Core 36A-17-andout 3/31/00 1:47 PM Major Again, the predominant product has the wrong stereochemistry and Winkler, J.D., et al. Tetrahedron Lett. 1993, 34, cannot be isomerized to the correct stereochemistry. Winkler, J.D., et al. Isr. J. Chem. 1997, 37, 47. Winkler, J.D., et al.tetrahedron 1998, 54, Winkler, J.D., et al. J. Am. Chem. Soc. 1998, 120,
19 (±)-Manzamine A Partial solution: The opposite diastereomer provides the desired stereochemistry C C Minor diastereomer of ketone reduction with ab 4. 1) hν, Pyrex C, 0 o C, 3 h 2) Et 3 Cl 3) DMAP 50% C Major dr 2.5:1.0 P Manzamine Core The correct stereochemistry is obtained as the major product, but Minor this substrate is synthetically inaccessible in high yield. Winkler, J.D., et al. Tetrahedron Lett. 1993, 34, Winkler, J.D., et al. Isr. J. Chem. 1997, 37, 47. Winkler, J.D., et al.tetrahedron 1998, 54, Winkler, J.D., et al. J. Am. Chem. Soc. 1998, 120, (±)-Manzamine A Ultimate solution: The olefinic linkage in the natural product provides for the correct stereoinduction Boc R 1) hν, Pyrex C, rt, 6 h Boc R 2) Pyr Ac 20% Steps See Rajapakse seminar Boc R Stereochemistry not determined Manzamine A R= 36A-18-andout 3/31/00 1:47 PM ne diastereomer Winkler, J.D., et al. Tetrahedron Lett. 1993, 34, Winkler, J.D., et al. Isr. J. Chem. 1997, 37, 47. Winkler, J.D., et al.tetrahedron 1998, 54, Winkler, J.D., et al. J. Am. Chem. Soc. 1998, 120, 6425.
20 (±)-Saudin Y Y Saudin MM2 calculations suggest that 1 should be approximately 1.6 kcal/mol more stable than Irradiation of the substrate (Pyrex, C/Acetone (9:1), 0 o C, 2 h) led to the formation of a 2.5:1 epimeric mixture of 2 in 97% yield. 2 * 4 Winkler, J.D., et al. J. Am. Chem. Soc. 1999, 121, Winkler, J.D., et al. Tetrahedron Lett. 1998, 39, (±)-Saudin Eleven steps 16% Saudin hν, Pyrex C/acetone (9:1) 0 o C, 30 min 80% ne diastereomer 1) n-buli, TF, TMEDA, -95 o C; Tf 2 2) (3-furyl)SnBu 3, LiCl, Pd(AsPh 3 ) 4, TF, reflux 77% PPTS, C % Li C 36A-19-andout 3/31/00 1:48 PM Winkler, J.D., et al. J. Am. Chem. Soc. 1999, 121, Winkler, J.D., et al. Tetrahedron Lett. 1998, 39, 2253.
21 Conclusions A lack of complete mechanistic understanding has not prevented the successful application of the enone-olefin photocycloaddition to a great many synthetic challenges. Intramolecular enone-olefin photocycloaddition is useful for the stereoselective contruction of carbocycles, especially five membered rings. Multiple quaternary and congested centers can be constructed in a single operation. Great creativity is possible in the fragmentation of the derived cyclobutane to access useful synthetic intermediates. Stereoinduction from existing stereocenters is usually explicable in a rational and satisfying manner. Molecular modeling simulations have proven useful in predicting the stereoselectivity of several photocycloadditions. 36A-20-andout 3/31/00 1:49 PM
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
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
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
CEM 852 Final Exam. May 6, 2010
CEM 852 Final Exam May 6, 2010 This exam consists of 7 pages. Please make certain that your exam has all of the necessary pages. Total points possible for this exam are 150. n answering your questions,
An Analysis of the Total Syntheses of Aphidicolin
An Analysis of the Total Syntheses of Aphidicolin An Evans Group Afternoon Seminar Krista Beaver March 20, 1998 A B D C Aphidicolin Isolated from the fungus Cephalosporium aphidicola (esp, Chem. Comm.1972,
Total Synthesis of (+/-)-Goniomitine via a Formal Nitrile/Donor-Acceptor Cyclopropane [3 + 2] Cyclization
![Total Synthesis of (+/-)-Goniomitine via a Formal Nitrile/Donor-Acceptor Cyclopropane [3 + 2] Cyclization](/thumbs/82/85235286.jpg "Total Synthesis of (+/-)-Goniomitine via a Formal Nitrile/Donor-Acceptor Cyclopropane [3 + 2] Cyclization")
Total Synthesis of (+/-)-Goniomitine via a Formal itrile/donor-acceptor Cyclopropane [3 + 2] Cyclization (-)-Goniomitine Christian L. Morales and Brian Pagenkopf* rganic Letters, ASAP Current Literature
Radical 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
Application of Two Direct C(sp 3 )-H Functionalizations for the Total Synthesis of (+)-Lactacystin
Application of Two Direct C(sp 3 )- Functionalizations for the Total Synthesis of (+)-Lactacystin two stereoselective C(sp 3 )- functionalisations 2 C S Ac (S)-pyroglutaminol (+)-lactacystin S. Yoshioka,
OC IV: Organic Photochemistry Exercise 1 Exercise class Page 1 of 11. Exercise 1: Fundamentals, H-Abstraction reactions
C IV: rganic otochemistry Exercise 1 Exercise class Page 1 of 11 Exercise 1: Fundamentals, -Abstraction reactions 1. Draw the energy potential curve of the ground state and the first two excited states
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
JOC: 1985 Year in Review
Baran Group eting JC: 1985 Year in eview Syntheses discussed: thodoligies discussed: Quadrone 2 C (+)-irsutic Acid C (±) Coriolin (!)-Longifolene (!)-astanecine Manganese (III)-mediated "-lactone annulation
Highlights 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
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
Total Syntheses of Nominine
Total Syntheses of ominine i Literature t Group eting Lizzie Bryan ctober 17, 2007 Aconite Alkaloids Atidane V eatchane Cycloveatchane Aconitane etisan Muratake,. M.; atsume, M.; akai,. Tetrahedron, 2006,
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
Enone Photochemistry: Fundamentals and Applications
Enone Photochemistry: Fundamentals and Applications Initial Discovery Ciamician and Silber were the first to report a 2 2 light-induced cycloaddition in 1908: Italian sunlight, one year carvone camphorcarvone
Midterm Exam #1 /280 CHEM 6352 Fall 2011
Midterm Exam #1 /280 CEM 6352 Fall 2011 ( %) Name Sept 30 th, 2011 18:00-21:00 You may NT use any references or aids to complete the following with the exception of a chemical model set and the scrap paper
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)
Hennoxazole A. Philip Williams Group Meeting December 12, OMe. OMe 1 6 O H
ennoxazole A 1 6 11 17 24 Philip Williams Group eting December 12, 2007 Discovered Discovered by Paul cheuer at the University of awaii in 1991. Isolated 480mg ennoxazole A from 4.5kg from the sponge Polyfibrospongia
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
Three 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
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;
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 +
VINBLASTINE. H MeO 2 C MeO. OAc. CO 2 Me. Me H
VIBLATIE 2 C 1 C 2 Ac a 3: catharanthine C 2 Ac C 2 2: ( )-vindoline xidation 5' 2 C 3' 16' 20' Ac C 2 1: (+)-vinblastine b 4 C 2 TFAA, -50 C Polonovski fragmentation 6' 5' 16' C 2 5 TFA 4' 3' 15' 16'
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
Olefin-Forming Reactions I
C549 R.M. Williams lefin-forming Reactions I The McMurry lefination Reaction. An important alternative to the acyloin condensation is the McMurry olefination which is a free radical coupling reaction initiated
CEM 852 Final Exam. May 5, 2011
CEM 852 Final Exam May 5, 2011 This exam consists of 8 pages. Please make certain that your exam has all of the necessary pages. Total points possible for this exam are 150. In answering your questions,
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,
James D. White. A very productive professor 64 students graduated from his lab 94 postdocs have worked in his lab. Education Experience
A very productive professor 64 students graduated from his lab 94 postdocs have worked in his lab Education Experience Fraser Fleming University of Drexel Pavel agory University of Michigan Cambridge University,
Recent Development in. Tandem Radical Reactions (TRR)
ecent Development in Tandem adical eactions (T) Feng u Jan. 13, 2006 Contents Brief Introduction of the istory of T Definition of T Intramolecular T Intermolecular T T as Key Steps in Total Synthesis of
Structures in equilibrium at point A: Structures in equilibrium at point B: (ii) Structure at the isoelectric point:
ame 21 F10-Final Exam Page 2 I. (42 points) (1) (16 points) The titration curve for L-lysine is shown below. Provide (i) the main structures in equilibrium at each of points A and B indicated below and
Total Synthesis of ( )-Himandrine
Total Synthesis of ( )-imandrine M. Movassaghi,* M. Tjandra and J. Qi J. Am. hem. Soc. 2009, 131, 9648-9650 Bz Adam T. oye urrent Literature ctober 3, 2009 Adam oye @ Wipf Group Page 1 of 22 10/3/2009
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
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
Chem 242b Chemical Synthesis
Lecture 7 [2+2] Cycloaddition Strategies 7A. verview of Ketene Cycloaddition Strategies (andout 4) If you need a cyclobutanone and desire to make it by [2+2] addition of ketene to an olefin, you will always
The 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
Massachusetts Institute of Technology Organic Chemistry Problem Set 1. Functional Group Transformations Study Guide
Massachusetts Institute of Technology rganic Chemistry 5.511 Problem Set 1 September, 2007 Prof. Rick L. Danheiser Functional Group Transformations Study Guide The purpose of this three-part study guide
Synthetic Developments Towards the Preparation of Erythromycin and Erythronolide Derivatives
ynthetic Developments Towards the Preparation of Erythromycin and Erythronolide Derivatives Russell C. mith Denmark Group Meeting 8-9-2005 most extensive project in organic synthesis this phenomenon is
Total Synthesis of the Proposed Structure of Briarellin J
Total Synthesis of the Proposed Structure of Briarellin J Michael T. Crimmins, Mark C. Mans, and Abimael D. Rodríguez. rg. Lett. 2010, ASAP Ac Ac originally proposed structure revised structure Eric E.
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
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.
Total Synthesis towards Maoecrystal V
Total Synthesis towards Maoecrystal V isolated from the leaves of a Chinese medicinal herb, Isodon eriocalyx in 2004. structure was determined by comprehensive NMR and MS spectroscopic analysis and confirmed
Chapter 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
Classics in Tetrahedron Letters
Classics in Tetrahedron Letters Jeremy Richter Baran Group Meeting: 9/24/03 The Plan Methodology Protecting Groups atural Products Syntheses Methodology xidation of Vicinal Diols R R' R'' 1. Cl 2, DMS,
JACS ASAP Article: Published 3/12/08. Lei Jiao, Changxia Yuan and Zhi-Xiang Yu. Current Literature: 3/29/08. David Arnold
Tandem h(i)-catalyzed [(5+2)+1] Cycloaddition/Aldol eaction for the Construction of Linear Triquinane Skeleton: Total Syntheses of (+)-irsutene and (+)-1- Desoxyhypnophilin JACS ASAP Article: Published
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%
JACS 1982: A Survey of Papers with a Focus on Synthetic Organic Chemistry
JAC 1982: A urvey of Papers with a Focus on ynthetic rganic Chemistry Baran Lab Group eting 15 ctober 2003 Carlos A. Guerrero eagents and thods 1 2 [] 2 2 1 1 PhC, Et 3 2 [] 2 1 2 1 By 1982, the [3 + 2]
Answers 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
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
Asymmetric 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.
Synthetic Efforts Toward Palau'amine
ynthetic Efforts Toward Palau'amine Doug Behenna, Ryan McFadden Eric Ashley, Jenn tockdill Akihiko Iwashita August 9, 2004 2 2 2 Isolation of Palau'amine and Congeners R 2 R 1 R 1 R 2 2 2 2 2 2 2 R 1 =
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
April 2002 CUME Organic Chemistry Department of Chemistry University of Missouri Columbia Saturday, April 6th, 2002 Dr.
April 2002 CUME Organic Chemistry Department of Chemistry University of Missouri Columbia Saturday, April 6th, 2002 Dr. Rainer Glaser Announced Reading: Prins Cyclization Reactions 1 Question 1. Aldol-Prins
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
EWG EWG EWG EDG EDG EDG
Functional Group Interconversions Lecture 4 2.1 rganic Synthesis A. Armstrong 20032004 3.4 eduction of aromatic systems We can reduce aromatic systems to cyclohexanes under very forcing hydrogenolytic
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
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
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
Higher Order Cycloadditions in Synthesis
'Malley igher rder Cycloadditions in Synthesis otes on Mechanism The cyclodimerization of alkenes and alkynes is a fundamental transition metal mediated process. This is the basic step in the mechanism
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
Requirements for an Effective Chiral Auxiliary Enolate Alkylation
Requirements for an Effective Chiral Auxiliary Enolate Alkylation 1. Xc must be low cost, and available in both enentiomeric forms 2. The cleavage of Xc from the substrate must occur under mild enough
Tips 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%
Hirsutene and Δ 9(12) Capnellene. D. P. Curran (1986) Presenter: Mehdi Moemeni
irsutene and Δ 9(12) Capnellene D. P. Curran (1986) Presenter: Mehdi Moemeni Back Ground of Radical Structure In a modern context the first organic free radical identified was triphenylmethyl radical.
When something goes wrong. Goya: Mother showing her derformed child to two women Louvre, Paris
1 ew Catalytic Asymmestric eactions Karl Anker Jørgensen Danish ational eserach Foundation: Center for Catalysis Department of Chemistry, Aarhus University Denmark kaj@chem.au.dk When something goes wrong
CEM 852 Exam-2 April 11, 2015
CEM 852 Exam-2 April 11, 2015 This exam consists of 6 pages. Please make certain that your exam has all of the necessary pages. Total points possible for this exam are 100. In answering your questions,
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
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
Organic Chemistry Qualifying and Comprehensive Exam
rganic Chemistry Qualifying and Comprehensive Exam Chemistry Division Illinois Institute of Technology April 16 th, 2010 Page 1 of 9 Instructions: This is a closed book exam and you have three hours to
O H HO H. !-D-galactopyranose
ame Key W06-Exam o. Page I. ( points) A disaccharide is cleaved by a β-glycosidase, an enzyme that specifically hydrolyzes a β- glycosidic linkage. When the disaccharide is treated with excess dimethyl
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
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
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
Introduction to Synthesis: Design (CHE686) Spring 2015 Exam #1 3/6/15
Introduction to ynthesis: Design (CE686) pring 2015 Exam #1 3/6/15 AME: KEY ome Pointers: 1. ELAX!! 2. ead the instructions for each question carefully. Be sure you understand what is required. If you
Towards Maoecrystal V: A Comparison of Recent Strategies
Towards Maoecrystal V: A Comparison of Recent Strategies Reactant/Reagent Current Literature: November 14, 2009 lissa Sprachman lissa Sprachman @ Wipf Group Page 1 of 14 12/28/2009 Maoecrystal V: Structural
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
Given that conditions for pyrazine formation have been established in prior
Chapter 2 Efforts in ur Laboratory 17 Chapter 2 Efforts in ur Laboratory 2.1 RETRSYNTETIC ANALYSIS Given that conditions for pyrazine formation have been established in prior synthetic reports by Shair
Catalytic Reactions in Organic Synthesis
17 April, 2008 Catalytic eactions in rganic Synthesis hodium Complexes and edox Catalysts Koichi AASAKA, Motoki YAMAE, Shunsuke CIBA Division of Chemistry and Biological Chemistry, School of ysical and
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
A Review of Total Synthesis of Spirotryprostatin A and B. Jinglong Chen Supergroup meeting Princeton University June
A Review of Total Synthesis of Spirotryprostatin A and B Jinglong Chen Supergroup meeting Princeton University June 28 2006 ovel Mammalian Cell Cycle Inhibitors, Spirotryprostatins A and B Me Spirotryprostatin
What is in Common for the Following Reactions, and How Do They Work?
What is in Common for the Following Reactions, and ow Do They Work? You should eventually be able to draw the mechanism for these (and other) reactions 13 Key Intermediate 1 Br-Br Na Br 2 C 3 -I Me NaMe
Name: CHEM 633: Advanced Organic Chemistry: Physical Final Exam. Please answer the following questions clearly and concisely.
Name: 1 CEM 633: Advanced rganic Chemistry: Physical Final Exam Please answer the following questions clearly and concisely. You may write your answers in the space provided and/or on additional pages.
Cis Trans Proline Isomerization Effects on Collagen Triple-Helix Stability are Limited
Cis Trans Proline Isomerization Effects on Collagen Triple-Helix Stability are Limited an Dai and Felicia A. Etzkorn* Department of Chemistry, Virginia Tech, Blacksburg, VA 24061-0212 Supporting Information.
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
Memory of Chirality: A Strategy for Asymmetric Synthesis
Memory of Chirality: A trategy for Asymmetric ynthesis David J. Richard eptember 14, 2005 Two Forms of Chirality Absolute (tatic) Chirality 2 - Absolute chirality - orientation of functional groups at
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
Total Syntheses of Minfiensine
Total Syntheses of Minfiensine Douany, A. B.; umphreys, P. G.; verman, L. E.*; Wrobelski, A. D., J. Am. Chem. Soc. 2008, ASAP. D: 10.1021/ja800163v Shen, L.; Zhang, M.; Wu, Y.; Qin, Y.*, Angew. Chem. nt.
Synthesis of Azadirachtin: A Long but Successful Journey
ynthesis of Azadirachtin: A Long but uccessful Journey Gemma E. Veitch, Edith Beckmann, Brenda J. Burke, Alistair Boyer, arah L. Maslen, and teven V. Ley Angew. Chem. Int. Ed. 2007, Early View And Gemma
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.
CHEM 330. Final Exam December 11, This a closed-notes, closed-book exam. The use of molecular models is allowed. This exam contains 12 pages
CEM 330 Final Exam December 11, 2007 Your name: This a closed-notes, closed-book exam The use of molecular models is allowed This exam contains 12 pages Time: 2h 30 min 1. / 20 2. / 20 3. / 30 4. / 40
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
Enantioselective Protonations
Enantioselective Protonations Marc Timo Gieseler 25.02.2013 15.03.2013 Group Seminar AK Kalesse 1 verview Introduction Enantioselective Protonation of Cyclic Substrates Enantioselective Protonation of
Approaches to the Synthesis. of Tetrahydropyrans. (and closely related heterocycles)
Approaches to the Synthesis of Tetrahydropyrans (and closely related heterocycles) William Morris Literature Presentation July 6, 2004 I. Intro A Nomenclature B Prevalence in Nature C Biosynthetic Considerations
Final Exam /340 ( CHEM 6352 Fall %) Name
Final Exam /340 ( CEM 6352 Fall 2012 %) Name Dec. 15 th, 2012 9:30-13:45 You may NT use any references or aids to complete the following with the exception of a chemical model set and the scrap paper that
Facile preparation of α-amino ketones from oxidative ring-opening of aziridines by pyridine N-oxide
Facile preparation of α-amino ketones from oxidative ring-opening of aziridines by pyridine -oxide rg. Biomol. Chem., 2007, 5, 3428 Luo, Z.-B.; Wu, J.-Y.; ou, X.-L.; Dai, L.-X. Ts toluene Ts 80 o C John
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
Free Radical Reactions in Synthetic Organic Chemistry
Free adical eactions in ynthetic rganic Chemistry C549.M. Williams Free radical intermediates have been utilized with varying degrees of success in the stereocontrolled formation of C-C bonds. Among the
Metal 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
[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
Enan$oselec$ve Total Synthesis of Amphidinolide F
Enan$oselec$ve Total Synthesis of Amphidinolide F Subham Mahapatra and ich G. Carter regon State University Angew. Chem. nt. Ed., 2012, 51, 7948 Nicolas Millius Bern, 07.02.2013 ntroduc$on isolated from
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.