SELECTIVE PREPARATION AND CYCLIZATION OF 2-(2-HYDROXYPHENYL)-2-(ISOPROPYLTHIO)ETHANOLS. NEW SYNTHESIS OF 1-BENZOFURANS
Reaction of phenols with 2-(isopropylthio)ethyl acetate activated by sulphuryl chloride afforded 2-phenols regioselectively, via sigmatropic rearrangement of phenoxysulphonium ylides.The ortho-alkylated phenols thus obtained have been cyclized with conc. hydrochloric acid in 2-methoxyethanol to 1-benzofurans. 2-Methyl- and 2-phenyl-1-benzofurans have been prepared similarly.