N-Boc-aminals as easily accessible precursors for less accessible N-Boc-imines: Facile synthesis of optically active propargylamine derivatives using Mannich-type reactions

Article abstract of DOI:10.1016/j.tet.2016.03.076

We developed a facile and practical synthesis of N-Boc-aminals, which can be used as precursors for less accessible N-Boc-imines. Aminals were obtained via simple dehydration condensation reactions of t-butyl carbamate (BocNH₂) and various aldehydes in acetic anhydride, followed by filtration and washing with hexane. The obtained N-Boc-alkynylaminals could be successfully applied in enantioselective Mannich-type reactions, catalyzed by chiral phosphoric acids, to afford optically active propargylamine derivatives.