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Pitt CHEM 2320 - Jacobsen Katsuki Epoxidations

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P Wipf Chem 2320 1 2 15 2006 9 Jacobsen Katsuki Epoxidations Jacobsen JACS 1990 112 2801 JACS 1991 113 7063 Katsuki THL 1990 31 7345 Based on Kochi s achiral salen catalyst Mcgarrigle E M Gilheany D G Chromium and manganese salen promoted epoxidation of alkenes Chem Rev 2005 105 1563 1602 Application in process chemistry THL 1995 36 3993 The use of the co catalyst P3NO allowed for a decreased charge of the Mn salen catalyst in the Jacobsen epoxidation P3NO stabilized the catalyst increased the rate and transported bulk oxidant HOCl into the organic phase JOC 1997 62 2222 1 P Wipf Chem 2320 2 2 15 2006 Mechanistic considerations Linker T Angew Chem Int Ed Engl 1997 36 2060 Preferred directions of attack of alkenes according to Jacobsen a and Katsuki b 3 possible mechanisms regarding the oxygen transfer to the double bond Epoxidation of styrene derivatives leads to mixtures Radical clock experiments give conflicting results There is clear evidence for the formation of radical intermediates however manganooxetanes for which there is electrospray MS evidence can also play a part in the mechanism The influence of reaction conditions has to be taken into account 2 P Wipf Chem 2320 3 2 15 2006 Nielsen L P C Stevenson C P Blackmond D G Jacobsen E N Mechanistic investigation leads to a synthetic improvement in the hydrolytic kinetic resolution of terminal epoxides HKR J Am Chem Soc 2004 126 1360 1362 The salen Co III complex 1 provides a general and effective method for the preparation of enantioenriched terminal epoxides 1a is the most commonly used variant The catalyst shows a second order dependence and a cooperative bimetallic mechanism has been suggested Dominant catalytic cycle in HKR reactions RDS rate determining step 3 P Wipf Chem 2320 4 2 15 2006 10 Peracid Peroxide Epoxidations Standard peracids are MCPBA CH3CO3H MMP CF3CO3H 3 5 dinitroperbenzoic acid 4 P Wipf Chem 2320 5 2 15 2006 Yang D Wong M K Yan Z Regioselective intramolecular oxidation of phenols and anisoles by dioxiranes generated in situ J Org Chem 2000 65 4179 4184 Singleton D A Merrigan S R Liu J Houk K N Experimental geometry of the epoxidation transition state J Am Chem Soc 1997 119 3385 Transition state for DMD Jenson C Liu J Houk K N Jorgensen W L Elucidation of transition structures and solvent effects for epoxidation by dimethyldioxirane J Am Chem Soc 1997 119 12982 5 P Wipf Chem 2320 6 2 15 2006 Epoxidation under Payne conditions Bachmann C Gesson J P Renoux B Tranoy I Tetrahedron Lett 1998 39 379 With the less acidic MCPBA epoxidation of allylic ethers is directed by steric hindrance and is antiselective Diastereomeric control in the epoxidation with peracids is quite good if appropriate directing groups are present or if the substrate is sterically biased 6 P Wipf Chem 2320 7 2 15 2006 Wipf P Kim Y Fritch P C J Org Chem 1993 58 7195 Diastereocontrol in acyclic substrates Kishi Y et al Tetrahedron Lett 1980 21 4229 7 P Wipf Chem 2320 8 2 15 2006 mechanistic consideration of the relative stability of ground state conformational isomers more calc Houk K N J Am Chem Soc 1991 113 5006 8 P Wipf Chem 2320 9 2 15 2006 Furan to pyrenone conversion Ireland R E Wipf P Roper T D J Org Chem 1990 55 2284 Preparation of a masked aldol system An example of the Achmatowicz reaction Catalytic Asymmetric Epoxidation with Chiral Dioxiranes Wang Z Y Tu Y Frohn M Shi Y J Org Chem 1997 62 2328 Biphasic reactions inexpensive oxidants turnover and catalytic efficiency need to be improved for this chemistry to become a viable competitor to transition metal catalysts for asymmetric epoxidation For recent progress see J Org Chem 1997 62 8622 Shi Y Organocatalytic asymmetric epoxidation of olefins by chiral ketones Acc Chem Res 2004 37 488 496 Yang D Ketone catalyzed asymmetric epoxidation reactions Acc Chem Res 2004 37 497 505 9 P Wipf Chem 2320 10 2 15 2006 Epoxidation of enones H2O2 t BuO2H cumene hydroperoxide 10 P Wipf Chem 2320 11 2 15 2006 Ooi T Ohara D Tamura M Maruoka K Design of new chiral phase transfer catalysts with dual functions for highly enantioselective epoxidation of unsaturated ketones J Am Chem Soc 2004 126 6844 6845 Presently limited to aryl or t Bu ketones Kakei H Tsuji R Ohshima T Shibasaki M Catalytic asymmetric epoxidation of unsaturated esters using an yttrium biphenyldiol complex J Am Chem Soc 2005 127 8962 8963 11 P Wipf Chem 2320 12 2 15 2006 11 Alternative Methods for Epoxide Formations Epoxides from diols Martin T Soler M A Betancort J M Martin V S J Org Chem 1997 62 1570 Gardinier K M Leahy J W J Org Chem 1997 62 7098 The basic transesterification required with standard esters in the final step of the Sharpless conversion of vicinal diols into epoxides Kolb H C Sharpless K B Tetrahedron 1992 48 10515 was incompatible with the target molecule cryptophycin 12 P Wipf Chem 2320 13 2 15 2006 Ireland R E Wipf P Roper T D J Org Chem 1990 55 2284 Via halohydrins Cardillo Epoxidation TH 1990 46 3321 13 P Wipf Chem 2320 14 2 15 2006 Guo J Duffy K J Stevens K L Dalko P I Roth R M Hayward M M Kishi Y Angew Chem Int Ed 1998 37 187 Arai S Shioiri T Catalytic asymmetric Darzens condensation under phase transfer catalyzed conditions Tetrahedron Lett 1998 39 2145 14 P Wipf Chem 2320 15 2 15 2006 Corey Chaykovski Reaction Aggarwal V K Ford J G Fonquerna S Adams H Jones R V H Fieldhouse R Catalytic Asymmetric Epoxidation of Aldehydes Optimization Mechanism and Discovery of Stereoelectronic Control Involving a Combination of Anomeric and Cieplak Effects in Sulfur Ylide Epoxidations with Chiral 1 3 Oxathianes J Am Chem Soc 1998 120 8328 8339 Aggarwal V K Winn C L Catalytic asymmetric sulfur ylidemediated epoxidation of carbonyl compounds Scope selectivity and applications in synthesis Acc Chem Res 2004 37 611 620 11 Epoxide Opening Reactions Review Hanson R M Chem Rev 1991 91 437 15 P Wipf Chem 2320 16 2 15 2006 on rings trans diaxial opening is preferred F rst Plattner rule Wipf P Lim S J Am Chem Soc 1995 117 558 Wipf P Lim S Chimia 1996 50 157 16 P Wipf Chem 2320 17 2 15 2006 Yamamoto H et al J Am Chem Soc 1989 111 6431 17


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Pitt CHEM 2320 - Jacobsen Katsuki Epoxidations

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