Lycoricidine and pancratistatin analogues from cyclopentadiene

Abstract

Concise synthetic routes from cyclopentadiene 4 to the lycoricidine and pancratistatin analogues 13, 14 and 17 have been developed. The key step involved the silver isocyanate promoted ring opening of the gem- dibromocyclopropane 6 to give, after interception of the intermediate isocyanates by added methanol, the carbamates 7 and 8. The X-ray crystal structures of compounds 13 and 16 have been determined.