Photodriven Enantioselective 6- <i>endo</i> Hydroaminative Cyclization to Chiral 4-Substituted 3,4-Dihydroisoquinolones

A photocatalytic asymmetric protocol for the synthesis of chiral dihydroisoquinolone scaffolds, which are prevalent in natural products and pharmaceuticals, has been developed. Utilizing chiral <i>C</i>₂-symmetric arylthiol as an H atom transfer catalyst, the enantioselective hydroamination-cyclization provides efficient access to a wide range of valuable 4-substituted 3,4-dihydroisoquinolones with moderate to high regio- and enantioselectivity. The synthetic utility of this methodology is demonstrated by the formal synthesis of several bioactive alkaloid intermediates.