Trialkylborane as an Initiator and Terminator of Free Radical Reactions. Facile Routes to Boron Enolates via α-Carbonyl Radicals and Aldol Reaction of Boron Enolates

Abstract

Abstract A variety of trialkylborane-induced reactions were examined for the preparation of the α-carbonyl radicals: (1) addition of alkyl radical to methyl vinyl ketone, (2) reduction of α-halo ketone, and (3) intramolecular radical addition to α,β-unsaturated carbonyl moiety. Trialkylborane reacted with α-carbonyl radicals to give boron enolates. The resulting boron enolates were efficiently trapped by carbonyl compounds to give β-hydroxy ketones in good yields.