Recent Advances in Asymmetric Hydrogenation of Tetrasubstituted Olefins.

The asymmetric hydrogenation of tetrasubstituted olefins provides direct access to very useful biological molecules and intermediates. The development of the technology has been slow, due in part to the synthetic challenges involved in developing chiral catalysts for a successful asymmetric induction. We briefly recount the breakthroughs in functionalized and unfunctionalized tetrasubstituted olefins, from the reports of Zhou and Buchwald for functionalized and unfunctionalized substrates, respectively, to the advent of chiral phosphoramidite ligands. The main emphasis of this Perspective lies in bringing into focus the complexity and challenges of inducing an asymmetric reduction for these substrates, which includes a brief discussion of the mechanism, the latest developed chiral catalysts, and the enormous scientific opportunities that still exist in developing "go to" catalyst systems for the various substrate types.