Diastereoselective Allylation of Aldehydes by Dual Photoredox and Chromium Catalysis

Herein, we report
the redox-neutral allylation of aldehydes with
readily available electron-rich allyl (hetero-) arenes, β-alkyl
styrenes and allyl-diarylamines. This process was enabled by the combination
of photoredox and chromium catalysis, which allowed a range of homoallylic
alcohols to be prepared with high levels of selectivity for the anti diastereomer. Mechanistic investigations support the
formation of an allyl chromium intermediate from allylic C­(sp3)–H bonds and thus significantly extends the scope
of the venerable Nozaki–Hiyama–Kishi reaction.