HIGHLY ENANTIOPURE (TERT-BUTYLDIPHENYLSILYLOXYMETHYL)OXIRANES FROM BARIUM CARBONATE

The synthesis of (2R)-(tert-butyldiphenylsilyloxymethyl)oxirane and th e (2S)-enantiomer from barium carbonate was developed. Methyl glycolat e or the hydroxamate analog was prepared and in turn reacted with (S)- (-)-methyl p-tolylsulfoxide or the (R)-enantiomer to make P-keto sulfo xides. From the sulfoxides, we made the diastereoisomeric alcohols in a highly selective sulfoxide group directed hydride reduction, and a P ummerer rearrangement reaction followed by deprotection yielded the en antiomeric diols. (2R)-(tert-Butyldiphenylsilyloxymethyl)oxirane and i ts (2S)-enantiomer were derived from these diols in an overall yield o f 56 % from barium carbonate. This method was developed to provide a c onvenient access to isotope-labeled analogs of these compounds.