New Perspectives in Lithium Carbenoid Mediated Homologations

α-Functionalized organolithium reagents (e.g., LiCH2X) are versatile reagents for accomplishing homologations of carbon- and heteroatom-type electrophiles. The proper selection of the reaction conditions allows one to direct their intrinsic ambiphilicity towards the nucleophilic character. Herein, the homologation of various electrophiles ranging from Weinreb amides to isocyanates, carbonyl derivatives, and chalcogenides - with a particular focus on the chemoselectivity of the processes - is summarized. 1 Introduction 2 Homologation of Weinreb Amides 3 Homologation of Cyclic Ketones 4 Homologation of Isocyanates 5 Homologation of Disulfides and Diselenides 6 Conclusions.