Facile and rapid route for the synthesis of novel conformationally constrained norstatine analogs via PADAM-cyclization methodology.

The following report describes novel methodology for the rapid synthesis of unique conformationally constrained norstatine analogs of potential biological relevance. A PADAM (Passerini reaction - Amine Deprotection - Acyl Migration reaction) sequence is followed by a TFA-mediated microwave-assisted cyclization to generate the final benzimidazole isostere of the norstatine scaffold in moderate to good yields. The applicability of this solution phase methodology to the preparation of a small collection of compounds is discussed.