Preparation of both enantiomers of cyclopropane derivatives from the reaction of vinyl selenones with di -(-)-bornyl malonate

The reaction of vinyl selenones with di-(-)-bornyl malonate and sodium hydride occurred with low diastereoselectivity and afforded a mixture of two diastereomeric cyclopropane derivatives in comparable yields. These, however, could be easily separated by chromatography. Removal of the bornyl group afforded highly enantiomerically enriched cyclopropanes. An example of the simple conversions of these cyclopropanes into the useful cyclopropane alpha-amino acids is also illustrated. The syntheses of several vinyl selenides and selenones are also described.