Switchable synthesis of sulfinylated and sulfonylated indoles and benzofurans from o-aminophenyl/o-hydroxyphenyl propargyl alcohols and β-sulfinyl esters

Abstract

The cascade reaction of o-aminophenyl/o-hydroxyphenyl propargyl alcohols with β-sulfinyl esters was explored under basic conditions. o-Aminophenyl propargyl alcohols were converted into 3-sulfinyl indoles using KOH, while 3-sulfonyl indoles were obtained using Cs₂CO₃ and CuI. o-Hydroxyphenyl propargyl alcohols were only compatible with the sulfonylation process using Cs₂CO₃ and CuI, delivering 3-sulfonyl benzofurans.