Visible-light-induced synthesis of indanones via the annulation of α-hydroxy ketones and alkynes.

A visible-light-induced annulation of α-hydroxy ketones with alkynes afforded 32 indanones in 30-73% yields under transition-metal- and external-photocatalyst-free conditions. α-Hydroxy ketones serve as the photoactive species, acyl source, and reductant. The strategy was further applied to the synthesis of pauciflorol F, isopauciflorol F, and indatraline.