Formaldehyd-O-oxid und Colchicine: ein eleganter Zugang zu Allocolchicinen

Abstract

Formaldehyde-O-oxide and Colchicine: An Elegant Route to the Allocolchicines Tropone is a structural unit of numerous natural products i.e. imerubrine, harringtonolide and colchicine (2). It is of interest to study the selectivity of formaldehyde-O-oxide (1) with respect to these polyfunctional tropone derivatives. We report about the reactions of 1 with colchicine (2) and the colchicine derivatives 5, 8, 11, 14, 17, 20 under ozone free conditions. The fragmentation of the spiroozonides 3, 6, 9, 12, 15, 18, 21via the activated complexes 3a, 6a, 9a, 12a, 15a, 18a, 21a opens up an elegant route to the allocolchicines 4, 7, 10, 13, 16, 19.