Rhodium(III)-Catalyzed Regioselective C(sp²)–H Functionalization of 7-Arylpyrazolo[1,5-<i>a</i>]pyrimidines with Dioxazolones as Amidating Agents

Abstract

Rh(III)-catalyzed C-H functionalization of 7-arylpyrazolo[1,5-<i>a</i>]pyrimidines was developed wherein the pyrazolo[1,5-<i>a</i>]pyrimidine moiety is reported for the first time to direct the C-H bond activation. Various 7-arylpyrazolo[1,5-<i>a</i>]pyrimidines underwent smooth C-H amidation with alkyl-, aryl-, and heteroaryl-substituted dioxazolones to afford the products in moderate to good yields. Mechanistic studies suggest that a six-membered rhodacycle intermediate involving N1 might play a key role in the regioselective catalytic cycle.