Concise Construction Of Sarain A Core According To A Biosynthetic Proposal: Cyclization Through An Intramolecular Mannich-Type Reaction Involving An Endocyclic N-Acyliminium Ion

Biogenetically inspired cyclization: The formation of the diazatricyclic core of the marine alkaloid sarain A was achieved, guided by a biosynthetic proposal. The main features are the regioselective reduction of a cyclic imide and an unprecedented intramolecular Mannich-type reaction involving an endocyclic N-acyliminium ion and a silyl enol ether (see scheme). Both species were generated in a single step and with a single reagent through electrophilic and nucleophilic activation. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.