Mechanistic insights into Rh(III)-catalyzed C[sbnd]H activation/annulation of N-Aryloxyacetamides with alkynyloxiranes

Abstract

Nowadays, transition metal catalyzed CH activation has been emerged as an attractive alternative tool for the functionalization of aromatic system. One such CH activation/annulation of N-Aryloxyacetamide with alkynyloxirane under the catalysis of Rh(III)-complex has been studied theoretically by employing density functional theory (DFT) to find out the plausible mechanistic path. The metal mediated annulation of various N-Aryloxyacetamides include nine steps- coordination of substrate with catalyst, NH metallation, CH metallation, insertion of alkynyloxirane, ring compression, Rh-migration, proton transfer (oxygen to nitrogen), proton transfer (oxygen to oxygen) and hetero cyclic ring formation. The effect of substituents on the mechanism has also been studied and the low energetic span obtained for this catalytic cycle implies that the reaction can proceed under room temperature. It is consistent with the experimental result.