An anomalous addition of chlorosulfonyl isocyanate to a carbonyl group: the synthesis of ((3a S,7a R, E)-2-ethyl-3-oxo-2,3,3a,4,7,7a-hexahydro-1 H-isoindol-1-ylidene)sulfamoyl chloride

Beilstein J Org Chem. 2019 Apr 16;15:931-936. doi: 10.3762/bjoc.15.89. eCollection 2019.

Abstract

In this study, we developed a new addition reaction of chlorosulfonyl isocyanate (CSI), starting from 2-ethyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3(2H)-dione. The addition reaction of CSI with 2-ethyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3(2H)-dione resulted in the formation of ylidenesulfamoyl chloride, whose exact configuration was determined by X-ray crystal analysis. We explain the mechanism of product formation supported by theoretical calculations.

Keywords: addition reaction; chlorosulfonyl isocyanate; sulfamoyl chloride; theoretical calculations.