Recent Developments in Nucleophilic Radical Addition to Imines: the Key Role of Transition Metals and the New Porta Radical-Type Version of the Mannich and Strecker Reactions

This review summarizes the interesting results obtained during the last decade in the radical aminoalkylation of a wide range of nucleophilic radicals (deriving from hydrocarbons, ethers, alcohols, halogenated derivatives and amides) promoted by transition metals. We focus on the two main procedures which recently yielded the most relevant results in this field: the dimethylzinc-air process and the new Porta reaction, based on the Ti( III)/hydroperoxide system. These protocols often provide competitive alternatives to classical landmark transformations, like the Mannich reaction and the Strecker synthesis. Moreover, a brief overview of other significant examples is given in the last section of the review.