Direct Synthesis of N-Acyl-N,O-hemia cetals via Nucleophilic Addition of Unactivated Amides and Their O-Acetylation: Access to alpha , alpha -Difunctionalized N-Acylimines

A mild, metal-free synthesis of polyfunctionalized N-acyl-N,O-hemia cetals was developed via the nucleophilic addition of unactivated amides to ketones. The protocol demonstrated a wide substrate scope, with good isolated yields. Additionally, their O-acetylated products serve as a precursor of alpha , alpha -difunctionalized N-acylimines. An addition reaction of broad scope of nucleophiles to generate N-acylimines is also reported.