Asymmetric [3 + 2] annulation of N-protected isatins with but-3-yn-2-one catalyzed by DIOP: facile creation of enantioenriched spiro[furan-2,3′-indoline]-2′,4(5H)-dione†
Abstract
DIOP catalyzed highly enantioselective [3 + 2] annulation of N-protected isatins with