Selective functionalization of alkanes by hydride transfer

Abstract

Selective functionalization of alkanes by hydride transfer is related to electrophilic activation of alkanes. The mechanism of hydride transfer is discussed in the light of isotopic labeling, kinetic isotope effects and theoretical calculations. Early examples of laboratory and industrial syntheses by hydride transfer are given. Applications to several reactions (Friedel-Crafts alkylations, halogenations, car☐ylations, Ritter reaction, etc.) are described and discussed; they are carried out under mild conditions and they give high yields and high regioselectivities. A general catalytic scheme is proposed in which a cationic intermediate is obtained from the alkane and further reacts with a nucleophile added to the reaction medium or gives a transfunctionalization. This scheme has been extended to electrophiles. The activation by hydride transfer is complementary to the activation of alkanes by superacids. The scope, advantages and limitations of selective functionalization of alkanes by hydride transfer are discussed.