EVIDENCE FOR THE FORMATION OF ACYLBORONATE INTERMEDIATES IN THE CARBONYLATION REACTIONS OF ORGANOBORANES

Trialkylboranes react with acyllithium reagents to yield ketones after oxidation with hydrogen peroxide. The ketones contain one alkyl group supplied by the alkyllithium reagent and one alkyl group supplied by the organoborane. The experimental results support the hypothesis that an acylboronate is an intermediate in the reactions of organoboranes with carbon monoxide. The yields are modest due to an apparent competi tion between carbon monoxide and organoborane for the alkyllithium nee ded to generate the acyl anion.