Synthesis of N-acyl-N,O-acetals mediated by titanium ethoxide.

N-Acyl-N,O-acetals are present in a number of bioactive natural products, and this unusual functional group can act as a synthetic precursor to unstable reactive N-acylimines. In this paper, a variety of N-acyl-O-ethyl-N,O-acetals was concisely prepared under mild conditions mediated by titanium ethoxide (Ti(OEt)4). The method also offers a new strategy to make other O-alkyl-N,O-acetals. Furthermore, this strategy was extended to the synthesis of an analogue of the natural product turtschamide.