DABCO-promoted highly diastereo- and regioselective construction of C-3 functionalized spirooxindoles [3 + 2] cycloaddition of 2-aryl/heteroarylidene-1-indene-1,3(2)-diones with -2,2,2-trifluoroethylisatin ketimines at ambient conditions.

The application of 2-aryl/heteroarylidene-1-indene-1,3(2)-dione as an activated olefin source in the DABCO-catalyzed [3 + 2] cycloaddition with -2,2,2-trifluoroethylisatin ketimines has been disclosed. This highly efficient 1,3-dipolar cycloaddition reaction offered a variety of trifluoro methyl group bearing spiro-pyrrolidine linked oxindoles with four consecutive stereocentres in good to excellent yield and excellent diastereoselectivity. The synthetic practicality of the protocol was established by demonstrating the enantioselective construction of spiro-pyrrolidine-oxindoles with two vicinal spiro-quaternary chiral centres in good yield excellent enantioselectivity (>90% ee) by using ultralow loading of quinine as the catalyst at room temperature.