Reactions of Aroxy- and Arylsulfanylacetic Acids and Their Esters with N-(2,2,2-Trichloro-1-hydroxyethyl)sulfonamides and -carboxamides

C-Amidoalkylation of aroxy- and arylsulfanylacetic acids and their methyl esters was effected by reaction with N-(2,2,2-trichloro-1-hydroxyethyl)sulfonamides and -carboxamides in the presence of methane- or trifluoromethanesulfonic acids as catalyst and solvent. The process is regioselective, and the substitution occurs at the para-position with respect to the heteroelement-containing group.