Synthesis of N-acylamidines via rhodium-catalyzed reaction of nitrosobenzene derivatives with N-sulfonyl-1,2,3-triazoles.

α-Imino rhodium carbene, readily generated from N-sulfonyl-1,2,3-triazole, underwent cycloaddition and subsequent rearrangement with a nitrosobenzene derivative to afford N-acylamidine. The unprecedented C-C bond cleavage of α-imino carbene was facilitated by the weakness of the N-O bond.

Synthesis of 3-pyrrolin-2-ones by rhodium-catalyzed transannulation of 1-sulfonyl-1,2,3-triazole with ketene silyl acetal.

α-Imino rhodium carbenoids generated from 1-sulfonyl 1,2,3-triazole were applied to the 3 + 2 cycloaddition with ketene silyl acetal, offering a novel and straightforward synthesis of biologically interesting compound 3-pyrrolin-2-one with broad substrate scope.

Synthesis of 3-aza-bicyclo[3.1.0]hexan-2-one derivatives via gold-catalyzed oxidative cyclopropanation of N-allylynamides.

N-allylynamides with various functional groups and different substitution patterns can be converted into 3-aza-bicyclo[3.1.0]hexan-2-one derivatives in moderate to high yield using IMesAuCl/AgBF4 as the catalyst and pyridine N-oxide as the oxidant. A noncarbene mediated approach is proposed as the mechanism.