Stephen A. Zderic

The reaction of B-alkyl-9-borabicyclo[3.3.1]nonanes with aldehydes and ketones. A facile elimination of the alkyl group by aldehydes

Abstract Certain B-alkyl-9-borabicyclo[3.3.1]nonanes (9-BBN) reduce benzaldehyde to benzyl alcohol under exceptionally mild conditions. Factors which contribute to a high rate of reaction include: an increase in the degree of substitution at the position β to the boron (isobutyl > 1-butyl >> ethyl), the ability of the alkyl group to form a syn-planar B—C—C—H conformation (cyclopentyl ⋍ norbornyl > sec-butyl >> cyclohexyl), and the presence of an electron-withdrawing para-substituent on the benzaldehyde (p-Cl > p-H > p-CH3O). The B-alkyl group is transformed into an olefin as the benzaldehyde is reduced. Elimination takes place predominantly if not exclusively towards the more highly substituted β hydrogen. The reaction obeys second order kinetics. The observations are consistent with a cyclic mechanism rather than a dehydroboration-reduction pathway.

The facile reaction of B-alkyl-9-borabicyclo[3.3.1]nonanes with benzaldehyde

Abstract Certain B -alkyl-9-borabicyclo[3.3.1]nonanes, in contrast to the corresponding trialkylboranes, reduce benzaldehyde to benzyl alcohol under exceptionally mild conditions. Concurrently, the B -alkyl group is transformed into an olefin. A cyclic process is proposed for this reaction.

Olefin-alkyl group exchange of B-alkyl-9-borabicyclo-[3.3.1]nonanes. Evidence for a dehydroboration-hydroboration process

Abstract B-Alkyl-9-borabicyclo[3.3.1]nonanes (9-BBN) undergo a rather facile olefin-alkyl group exchange process when refluxed with an olefin in tetrahydrofuran. Kinetic and competition studies support a dehydroboration-hydroboration process.