Intramolecular Copper-Catalyzed Asymmetric Propargylic [4 + 2]- Cycloaddition toward Optically Active Tetrahydroisoindolo[2,1- a ]quinoxalines.

An intramolecular Cu-catalyzed asymmetric propargylic [4 + 2] cycloaddition of bis- N -nucleophile-functionalized propargylic esters has been realized in the support of a chiral tridentate N-ligand, ( S , S )-Pybox-diOAc, leading to chiral tetrahydroisoindolo[2,1- a ]quinoxalines in high yields and with good to excellent enantioselectivities. The reaction features high efficiency, simplicity, and broad substrate scope, thus providing a powerful and concise strategy for stereoselective access to optically active polycyclic heterocycle frameworks that are otherwise difficult to synthesize.