On the mechanism of the reduction of carbonyl-contai ning compounds with a solution of diborane in tetrahydrofuran

Abstract

1. A solution of diborane in tetrahydrofuran readily reduces chloral and chlorides of aliphatic carboxylic acids possessing electronegative substituents. 2. The introduction of substituents possessing a -I effect decelerates the reduction of complex esters and accelerates the reduction acid chlorides. The rate of reduction of aldehydes passes through a minimum as electronegative substituents accumulate. 3. The influence of halogen and alkyl substituents on the rate of reduction is proportional to their inductive effect. 4. The hypothesis was advanced that the complex of tetrahydrofuran with monoborane can directly carry out the reduction of carbonyl-containing compounds(ketones, aldehydes, acid chlorides). The probability of such reduction increases as electronegative substituents accumulate in the compound to be reduced. 5. The character of the reduction of complex esters with a solution of diborane in tetrahydrofuran differs from the reduction of other carbonyl-containing compounds.