Visible-Light-Mediated Synthesis of N‑Acyl-N,O-hemiacetals from Terminal Alkynes: Access to N,N-, N,S-, and N,O-Acetals

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