Palladium-catalyzed enantioselective decarboxylative [3+2] cycloaddition of 5‑vinyloxazolidine-2,4-diones with sterically encumbered ketoimines toward chiral polycyclic 1,4-imidazolidinones

Abstract

A palladium-catalyzed decarboxylation of 5‑vinyloxazolidine-2,4-diones for in situ generation of aza-π-allylpalladium zwitterionic intermediates, which act as 1,3-N,C-dipoles in enantioselective [3+2] cycloaddition with sterically encumbered cyclic N-sulfonyl ketoimines was first developed. A series of chiral polycyclic 1,4-imidazolidinone derivatives bearing two quaternary carbon stereogenic centers were obtained in excellent results (up to 91% yield, >95:5 dr and 96% ee). This study also revealed that the N-alkoxy-substitution of 5 vinyloxazolidine-2,4-diones is crucial for the reactivity.