Enantioselective Total Syntheses of Lyconadins A-E through a Palladium-Catalyzed Heck-Type Reaction
Jiayang Zhang1, Yangtian Yan1, Rong Hu1
1Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
Abstract:
A novel palladium-catalyzed Heck-type reaction of thiocarbamates has been designed to construct bridged seven-membered-ring systems that are otherwise challenging to prepare. Taking advantage of this newly developed method, enantioselective syntheses of lyconadins A-E (1-5), lycopecurine (6), and dehydrolycopecurine (7) have been realized in a divergent fashion. Our synthetic strategy also features an intramolecular cyclization of a N-chloroamine to forge the C6-N bond, a transannular Mannich-type reaction of a cyclic nitrone to stitch the C4 and C13 together, and a cyclocondensation to deliver the (dihydro-)pyridone motif.
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