Conjugate addition reactions of carbon nucleophiles to electron-deficient dienes.

The conjugate addition reaction of carbon nucleophiles to electron-deficient olefins is one of the most reliable methods for selective C-C bond formation. However, the conjugate addition to the vinylogous electron-deficient dienes has been much less developed, as there is considerably more difficulty in controlling the regioselectivity of the addition to these extended conjugate systems due to the presence of three electrophilic sites, as well as the stereoselectivity. Although still underdeveloped, new approaches to tackle these challenges are beginning to emerge. Both transition-metal-catalyzed and organocatalytic approaches are currently being developed to cope with the main selectivity issues of this type of process: regioselectivity (1,2-, 1,4-, and 1,6-addition) and stereoselectivity (asymmetric formation of the new C-C bonds). In this tutorial review, we have surveyed representative examples to get an overview of the recent advances obtained in the scope of the conjugate addition reaction of carbon nucleophiles to electron-deficient dienes.