Direct Conversion of an ortho-Allylphenol into a Chlorosulfonyl-3-methyl-1,2-benzoxathiin 2,2-Dioxide

Abstract

A one-pot synthesis of methyl 6-chlorosulfonyl-3-methyl-1,2-benzoxathiin-8-carboxylate 2,2- dioxide (9), characterized as its 6-(4-methylpiperazin-1-yl)sulfonyl derivative 10, is achieved via direct reaction of methyl 3-allylsalicylate (1) with chlorosulfonic acid at −7°C. The latter reagent converts methyl 2-methyl-2,3-dihydrobenzofuran-7-carboxylate (3) into the respective 5-chlorosulfonyl derivative 7 (identified as its 5-(4-methylpiperazin-1-yl)sulfonyl derivative 8), while contrary to literature reports, the aromatic δ -sultones 9, 10 (anticipated to be produced from 3) were not detected.