Visible-Light-Mediated Synthesis of -Acyl--hemiacetals from Terminal Alkynes: Access to , , and Acetals.

A mild electron donor-acceptor complex-mediated approach for the synthesis of -acyl--hemiacetals has been reported. The key feature of this protocol is that it allows for direct access to electrophilic -acylimines at room temperature without prefunctionalization of the hydroxyl group. The generated -acylimine can react with different nucleophiles, viz., alcohols, thiols, and nitriles, to afford a diverse range of scaffolds such as -, -, and -acetals.