Asymmetric alkyl-alkyl cross-coupling enabled by earth-abundant metal-catalyzed hydroalkylations of olefins

Stereogenic carbon centers with C(sp)–C(sp) bonds are subunits extensively occur in natural products, bioactive targets, and chiral organic materials. Transition-metal-catalyzed C(sp)–C(sp) bond-forming processes represents one of the most ideal solutions to furnish such stereogenic centers. Over the past decades, numerous progress have been achieved in metal-catalyzed enantioselective alkyl-alkyl coupling between alkyl metallic reagents with alkyl electrophiles. However, preformation and use of stoichiometric amount of alkyl metallic reagents significantly limit the availability, scope, and further application of this strategy. Recently, in situ formation of alkyl metallic reagents enabled by hydrometallated of olefins has been emerging as one of the most promising alternatives to undergo asymmetric alkyl-alkyl cross-coupling, bypassing the use of stoichiometric preformed alkyl metallic reagents. In this perspective, recent progress in earth-abundant metal-catalyzed asymmetric hydroalkylations of olefin to enantioselectively build C(sp)–C(sp) bonds is highlighted. Moreover, mechanistic considerations of asymmetric hydroalkylation of olefin as well as challenges and future efforts are also discussed.