Transformation of Imines via Nickelacycles

In this chapter, three different types of nickel-catalyzed transformation reactions of imines, (a) [2 + 2 + 1] carbonylative cycloaddition to afford γ-lactams; (b) multi-component coupling or cyclocondensation reactions with alkylmetal reagents to yield allylamine derivatives; and (c) [2 + 2 + 2] cycloaddition reaction leading to 1,2-dihydropyridines, are summarized. In these transformations, five-membered aza-nickelacycles, which are generated via the oxidative cyclization of an imine and a unsaturated compound with Ni(0), are involved as a key reaction intermediate. These nitrogen-containing products are ubiquitous structural motifs for natural products in small molecules that have biomedical relevance and are among the most versatile synthetic intermediates for use in the preparation of a wide range of other valuable molecules.