Asymmetric [4+2] Annulations of Isatins with But-3-yn-2-one

The catalytic asymmetric [4+2]annulations of isatins with but-3-yn-2-one catalyzed by the Cinchona alkaloids-derived oragnocatalyst (DHQD)(2)PHAL have been developed in the presence of 3.0equivalents of D-diethyl tartrate in the mixed solvent (diphenyl ether/diethyl ether=1/1) or a slightly modified one, affording the corresponding substituted spiro[indoline-3,2-pyran]-2,4(3H)-diones in good to excellent yields with high enantioselectivities under mild conditions.