Enantioselective CuH-Catalyzed Hydroallylation of Vinylarenes

Abstract

The creation of configurationally well-defined stereogenic centers during the course of carbon–carbon bond formation is of great importance for the synthesis of complex organic molecules. Due to the synthetic versatility of the olefin functional group, the enantioselective installation of an allylic fragment has long been regarded as a particularly valuable subset of stereoselective C–C bond-forming transformations.(1-3) Among the numerous transition-metal-catalyzed methods for enantioselective allylation, the copper-catalyzed addition of organometallic reagents to allylic electrophiles is distinguished by its applicability to non-heteroatom-stabilized carbon nucleophiles.(4) As a consequence, these methods can be readily applied to the construction of C–C bonds remote from polar functional groups in an enantioselective manner, a process for which few other catalytic methods are available. In typical copper-catalyzed allylic substitution reactions, the organocopper intermediate undergoes addition to a prochiral allylic electrophile, resulting in the formation of a stereocenter α to a double bond. In contrast, the addition of an α-chiral organocopper species to an allylic electrophile to furnish a β-stereocenter has seldom been reported and would represent a significant advance (Figure 1A).(5)