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.