Selective N-demethylation of tertiary aminofumagillols with selenium dioxide via a non-classical Polonovski type reaction

The previously unknown selective N-demethylation of tertiary aminofumagillols (5a-e) to the corresponding secondary aminofumagillols (7a-c) is effectively accomplished via a non-classical Polonovski type reaction using selenium dioxide (SeO₂). Especially, noteworthy is that two epoxy and the α,β-unsaturated ester functionalities in the fumagillol molecules tolerate in this transformation. Aminofumagillol derivatives are valuable antiangiogenesis inhibitors.