Synthetic Approaches to the Challenging Direct C-Alkylation and C-Allylation of Unactivated Nitroalkanes

The limited nucleophilic character and the bidentate nature of unactivated nitroalkane anions (nitronates) makes the corresponding alkylation and allylation procedures rather troublesome. This aspect is in sharp contrast with other commonly employed processes involving nitronate anions such as conjugate additions or nitroaldol reactions. This review summarizes the most rewarding approaches that along the years have been devised to overcome this limitation. Efficient methods are nowadays mainly based on metal-catalyzed processes involving purely ionic or mixed ionic-radical intermediates including photoenzymatic reactions.