Lou M, Liu X, Han S, Bai S, Qi X. Total synthesis of (±)-3-demethoxyerythratidinone
via Tf
2O-promoted cascade reaction of enaminone.
Chem Commun (Camb) 2024;
60:3842-3845. [PMID:
38497323 DOI:
10.1039/d3cc06270h]
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Abstract
The tetracyclic rings with chiral quaternary center represent a formidable synthetic challenge for Erythrina alkaloids. We present a 6-step synthesis of the Erythrina alkaloid 3-demethoxyerythratidinone with a 16% overall yield. Our synthesis highlights a cascade reaction initiated by Tf2O-induced activation of an enaminone substrate, yielding an iminium species and an enol triflate, followed by a Pictet-Spengler reaction. This method efficiently constructs the tetracyclic core skeleton, featuring an N-substituted quaternary center. It exhibits versatility across diverse (hetero)arenes and enaminone structures, providing a general strategy for the rapid synthesis of fused or spiro ring systems including the core structure of homoerythrina alkaloids.
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