Y. Xu, D. Kohlman, and Sidney X. Liang
Oct 9, 1999
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0
Influential Citations
49
Citations
Journal
Organic Letters
Abstract
A formal total synthesis of pyranonaphthoquinone natural product deoxyfrenolicin 1 is described. The key step in the synthesis involves the use of stereoselective 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-induced C−C bond coupling of the naphthopyran 10 with allyltriphenyltin to give exclusively 1,3-trans naphthopyran derivative 23. The naphthopyran 10 was obtained via oxa-Pictet−Spengler cyclization of substituted naphthalene 22, which was derived by regioselective benzannulation of chromium carbene complex 12 with acetylene 18. This newly developed synthetic route employing a tandem benzannulation/oxa-Pictet−Spengler cyclization/DDQ-induced coupling strategy should also be applicable to the synthesis of other pyranonaphthoquinone natural products such as kalafungin 4 and nanaomycin 5.