Redox-neutral synthesis of π-allylcobalt complexes from alkenes for aldehyde allylation via photoredox catalysis

Abstract

This work reports the first visible-light mediated cobalt-catalyzed aldehyde allylation with simple alkenes to produce homo-allylic alcohols. This novel strategy directly uses easily available unactivated alkenes as alternative allyl sources instead of pre-synthesized allylic halides/alcohols, thus bypassing the need for exogeneous reductants. Mechanistic studies suggest that the unprecedented combination of allyl radical intermediates and Co^I species to generate nucleophilic π-allylcobalt^II under photoredox conditions represents the key step in the catalytic cycle.