Synthesis of CF3-Containing Bispirocyclic 2-Pyrrolidinones through Cycloaddition and Oxidative Dearomatization from Nitrones and 1-Alkynyl-2-naphthols.

Abstract

Herein, a variety of trifluoromethyl-containing bispirocyclic 2-pyrrolidinones were prepared in good yields with high diastereoselectivity through a cinchonidine-catalyzed (4 + 3) cycloaddition and oxidative dearomatization strategy from N-trifluoromethyl aryl nitrones and 1-alkynyl-2-naphthols under mild reaction conditions. Mechanistic studies revealed that PhI(OAc)2 played important roles in the formation of CF3-containing bispirocyclic 2-pyrrolidinones in the oxidation and dearomatization steps. The present method features high regioselectivity and diastereoselectivity, three rings and three carbon stereocenters formation, and novel bispirocyclic 2-pyrrolidinone scaffolds.