New selective reducing agent

Abstract

Zinc cyanoborohydride is prepared by the addition of 2 moles of sodium cyanoborohydride for every mole of anhydrous zinc chloride in diethyl ether. The reagent is reacted with ketones and organic halides in order to investigate the reducing characteristics of the reagent. The reagent in diethyl ether reduces ketones. However, $\alpha,\;\beta$-unsat. ketones and hindered ketones are inert to the reagent in a mixture of diethyl ether and water. The reagent reduces tertiary, allylic and benzylic halides to the corresponding hydrocarbons, while primary and secondary alkyl halides and vinyl halides are completely inert toward the reagent in diethyl ether.