Copper Carbenoid, Reactant and Catalyst for One‐Pot Diazo Ester Coupling Cascade Rearrangement of Enediynes: Formation of Two Contiguous Tetrasubstituted Stereocenters

Abstract

AbstractThe copper‐catalyzed reaction of enediynes with diazo esters leads to cyclic amino esters bearing two contiguous tetrasubstituted stereogenic centers through a one‐pot, five‐step cascade. Copper iodide catalyzes the formation of an intermediate 3‐alkynoate and copper carbenoid promotes its reversible isomerization to the corresponding allenoate. The alkynoate‐allenoate equilibrium is completely shifted to the right by the rapid consumption of the allenoate by Myers–Saito cyclization. This is followed by 1,5‐H atom transfer and recombination of the resulting biradical. Memory of chirality phenomenon explains the high enantioselectivity.