Preparation of 3‑Sulfonylated 3,3-Disubstituted Oxindoles by the Addition of Sulfinate Salts to 3‑Halooxindoles

An
efficient method for the preparation of 3-sulfonylated 3,3-disubstituted
oxindole derivatives has been developed. The protocol involves a base-catalyzed
addition of sulfinate salts to 3-halooxindoles, affording a wide range
of 3-sulfonylated 3,3-disubstituted oxindoles in good to excellent
yields under mild conditions. A preliminary trial of asymmetric catalytic
version was conducted and gave promising enantioselectivity. The mechanism
for the reaction was tentatively explored with the help of mass spectrometric
analysis.