Phosphine-Catalyzed Ring-Opening Regioselective Addition of Cyclopropenones with Amides.

A series of amides, including α-bromo hydroxamates, N -alkoxyamides, and N -aryloxyamides, were subjected to phosphine-catalyzed ring-opening O -selective addition with cyclopropenones, producing various special α,β -unsaturated esters containing oxime ether motif, in moderate to excellent yields, with high regioselectivity, and exclusive O -selectivity. The methodology is highly atom-economical, with simple operation procedures, and compatible with a wide substrate scope (more than 44 examples).