Lithium tri-sec-butylborohydride as a selective reducing agent in reduction of organic halides

Abstract

Lithium tri-sec-butylborohydride in tetrahydrofuran reduces rapidly simple primary alkyl, benzylic and allylic halides. The reduction of tertiary alkyl bromide is slow and results predominantly in elimination. Of special synthetic significance is the stoichiometric requirement of the reagent for the reduction of organic halides unlike other complex hydride reducing agents. Furthermore, employment of a stoichiometric amount of the reagent permits selective reduction of primary alkyl bromide into the corresponding alkane in the presence of primary alkyl chloride and secondary alkyl bromide.