An asymmetric synthesis of aza analogues of the tricyclic skeleton of daphnane and the ABC ring system of phorbol.

Charles M Marson, Jennifer H Pink, David Hall, Michael B Hursthouse, Abdul Malik, Christopher Smith

Index: J. Org. Chem. 68(3) , 792-8, (2003)

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Abstract

An asymmetric synthesis of aza analogues of the ABC ring system of phorbol and related compounds containing the 5-7-6-fused framework of daphnane involved construction of the central seven-membered ring by a regioselective reduction of a chiral imide and cyclization with trifluoromethanesulfonic acid. Subsequent demethylation and oxidative dearomatization of ring C afforded an enantiopure dienone 20 with the same relative and absolute configuration at the 9- and 10-positions of the phorbol skeleton.