ASYMMETRIC EPOXIDATION USING CHIRAL SULFUR YLIDES

Novel chiral sulfides, derived from pinene, have been prepared, converted to sulfonium salts and treated with base and aldehydes to generate non-racemic epoxides. Low to moderate enantioselectivities were obtained in the product epoxides and this possibly occurred as a result of using diastereomeric mixtures of sulfonium salts. Dibenzyl substituted sulfonium salts were also prepared to avoid formation of diastereomers but upon treatment with base and an aldehyde this gave the Stevens rearrangement product instead of epoxide.