Catalytic Asymmetric Allylation of Aldehydes with Alkenes Mediated by Organophotoredox and Chiral Chromium Hybrid Catalysis

A hybrid system accomplishing cooperativity between an organophotoredox acridinium catalyst and a chiral chromium
complex catalyst was developed, enabling the unprecedented exploitation of unactivated hydrocarbon alkenes as precursors to chiral allylchromium nucleophiles for the asymmetric allylation of aldehydes. The reaction proceeded under visible light irradiation at room temperature and with high functional group tolerance, affording the corresponding homoallylic alcohols with up to >20/1 diastereomeric ratio and 99% ee. The addition of Mg(ClO4)2 elicited profound enhancement of both reactivity and enantioselectivity.