Carbene Transfer and Carbene Insertion Reactions Catalyzed by a Mixed‐Ligand Copper(I) Complex

Abstract

The catalytic activity of the mixed‐ligand copper(I) complex [Cu(PPh3)2(κ2‐O,O"‐lact)] (1) {lact = l‐(+)‐lactate} has been investigated in carbene transfer and carbene insertion reactions. Complex 1 catalytically promoted the diastereoselective cyclopropanation of olefins in the presence of ethyl diazoacetate (EDA), under mild conditions, and with a low catalyst loading (1 mol‐%). In the case of internal alkenes, a trans/cis ratio of up to 93:7 was reached. Moreover, compound 1 easily promoted the insertion of the carbene fragment deriving from the decomposition of ethyl diazoacetate into O–H (alcohols and phenols) and N–H (amine) bonds, with formation of the corresponding ethyl 2‐alkoxyacetate, ethyl 2‐phenoxyacetate, and ethyl 2‐aminoacetate derivatives in good to high yields.