Thermally Stable “Cation Pool” For C-C and C-Heteroatom Bond Formation

Abstract

Thermally stable “ halogen cation pool” method was introduced with the initial reaction of DMSO and 1,2-dihaloethane generating the sulfonium ion, which undergoes pyrolytic elimination of ethylene gas by affording halonium ions. These ions were accumulated and stabilized by DMSO through coordination. Using this novel strategy 2-oxindoles were synthesized from indoles with initial halogenation reaction, while at 85 °C isatin derivatives were obtained. We have also extended our protocol for the synthesis of γ-Ketosulfones via C–C bond formation and β-morpholinoketones through C–N and C–C bond formation reactions under controlled reaction conditions from methyl Ketones.