Claisen rearrangement of allylic alcohols prepared through N-Boc-2-acyloxazolidine methodology. Application to the synthesis of trisubstituted cyclopropanes

Stereodefined allylic alcohols prepared from a (R)-phenylglycinol-derived Weinreb amide undergo a Claisen rearrangement with a high level of stereocontrol. The produced N-Boc-2-alcenyloxazolidines can be either hydrolyzed to afford enantiomerically enriched enals or further epoxidized using a two-step sequence. The resulting epoxyoxazolidines can then be transformed into trisubstituted cyclopropanes.