A rhodium(II)-catalyzed denitrogenative coupling of N-sulfonyl-1,2,3-triazoles with ambiphilic β-enamino esters affords 2,5-dihydro-1H-imidazoles (3-imidazolines) with broad functional group tolerance. Mechanistic studies using a deuterium-labeled triazole suggest that the reaction proceeds in a cascade through the N-H insertion of an α-imino rhodium-carbene, followed by enamine-imine tautomerization and conjugate addition. Moreover, the reaction proceeds with high diastereoselectivity for α-substituted β-enamino esters (R3 = Me, Ph) to give a single diastereomer. (Chemical Equation Presented).
|Number of pages||7|
|Journal||Journal of Organic Chemistry|
|State||Published - 17 Oct 2014|