Stereoselectivity in competing [1,2] and [1,3] rearrangements

Abstract

The competing intramolecular [1,2] and [1,3] rearrangements of the chiral ylide [1, R¹=(R)–CHMePh, R²= Me] are both stereoselective, giving the products (5) and (7) with predominant retention of the configuration of the migrating phenylethyl group; the stereoselectivity of the [1,2] rearrangement is significantly greater than that of the [1,3] rearrangement.