Enantioselective Total Synthesis of (−)-Minovincine in Nine Chemical Steps: An Approach to Ketone Activation in Cascade Catalysis
作者:Brian N. Laforteza、Mark Pickworth、David W. C. MacMillan
DOI:10.1002/anie.201305171
日期:2013.10.18
Dressed to the nines: The first enantioselectivetotalsynthesis of (−)‐minovincine has been accomplished in ninechemicalsteps and 13 % overall yield. A novel, one‐step Diels–Alder/β‐elimination/conjugate addition organocascade sequence allowed rapid access to the central tetracyclic core in an asymmetric manner. Boc=tert‐butoxycarbonyl, LG=leaving group, PMB=para‐methoxybenzyl.
Chiral Holmium Complex-Catalyzed Synthesis of Hydrocarbazole from Siloxyvinylindole and Its Application to the Enantioselective Total Synthesis of (−)-Minovincine
The catalytic and enantioselective total synthesis of (-)-minovincine has been accomplished. The key highly substituted hydrocarbazole derivative was obtained by an asymmetric Diels-Alder reaction of siloxyvinylindole catalyzed by 0.5 mol % of a chiral holmium complex. The Diels Alder adduct was converted to a tetracyclic intermediate in a one-pot procedure. No waste stereoisomers were produced throughout the entire total synthesis.