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Total Synthesis of (-) and (+)-Zingibergingerols A
Manoj N Shet1,2, Chepuri V Ramana1,2
1Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
Abstract:
The first total synthesis of both of the enantiomers of Zingibergingerol A has been accomplished. The distinctive 3,7,9-trioxabicyclo[4.2.1]nonane skeleton is crafted through gold-catalyzed alkynol cycloisomerization. The synthesis comprises sequential C-C bond formations at both ends of epichlorohydrin: first opening the epoxide with eugenol-derived alkyne, followed by subsequent epoxide installation, and again opening with a Grignard reagent. The resulting alkynol with a fixed C5 stereochemistry was subjected to O-allylation, followed by dihydroxylation and alkynol cycloisomerization.
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