Chemistry of organoborates. Part IV. Stereochemistry and relative migratory aptitudes of alkyl groups in the cyanoborate process

Abstract

All three possible migrations from boron to carbon in the cyanoborate process involve retention of configuration at the migrating centre. For each of the three migrations the relative migratory aptitudes of alkyl groups are in the order n- > s- > t-a result rationalised in terms of the charge density at carbon in the transition state. Products derived from certain di- and tri-substituted olefins should theoretically be mixtures of diastereoisomers and in one instance this has been verified.