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Synthesis of epoxides

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Key step in the synthesis of chiral phenyloxirane is the enantioselective catalytic reduction of an achiral chloromethyl ketone by means of a chiral oxazaborolidine as catalyst and borane as stoichiometric reductant.
E. J. Corey, S. Shibata, R. K. Bakshi, J. Org, Chem., 1988, 53, 2861-2863.

Dynamic kinetic resolution (DKR) of various aromatic chlorohydrins using Pseudomonas cepacia lipase (PS-C “Amano” II) and a ruthenium catalyst afforded chlorohydrin acetates in high yields and high enantiomeric excesses. These optically pure chlorohydrin acetates can be transformed to a wide range of important chiral compounds.
A. Träff, K. Bogár, M. Warner, J.-E. Bäckvall, Org. Lett., 2008, 10, 4807-4810.

Alkynyl halides serve as a source of Br⁺ and acetylide ions in an efficient one-step preparation of alkynyl epoxides, important organic building blocks, from readily available starting materials.
A. Trofimov, N. Chernyak, V. Gevorgyan, J. Am. Chem. Soc., 2008, 130, 13538-13539.

The aza-Payne rearrangement of 2,3-aziridin-1-ols under basic conditions gives epoxy amines. Subsequent nucleophilic attack of the epoxide by dimethylsulfoxonium methylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine. This process takes place with complete transfer of stereochemical fidelity and can be applied to sterically hindered aziridinols.
J. M. Schomaker, S. Bhattacharjee, J. Yan, B. Borhan, J. Am. Chem. Soc., 2007, 129, 1996-2003.