Lewis acid-catalyzed regioselective C–H carboxamidation of indolizines with dioxazolones via an acyl nitrene type rearrangement?

Organic Chemistry Frontiers Pub Date: 2021-04-01 DOI: 10.1039/D1QO00224D

Abstract

An efficient, direct, and novel Lewis acid-catalyzed regioselective C–H carboxamidation of indolizines with dioxazolones via an acyl nitrene type rearrangement under metal-free conditions has been documented. A diverse array of indolizine-3-carboxamides were achieved in moderate to good yields with wide substrate scope. In these transformations, isocyanatobenzene was formed by the ring opening of dioxazolones and a subsequent Curtius-type rearrangement, which could be harnessed in C–H carboxamidation of N-heterocycles. The present protocol is satisfactorily complementary to nitrene transfer chemistry and C–H functionalization of N-heterocycles. Furthermore, photophysical experiments revealed that a few compounds exhibited high fluorescence absorption and emission intensity.

Graphical abstract: Lewis acid-catalyzed regioselective C–H carboxamidation of indolizines with dioxazolones via an acyl nitrene type rearrangement
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