Rh()-catalyzed (5 + 2)-cycloaddition reactions of -hydroxyethyl phenols with internal alkynes: efficient synthesis of benzoxepines

An unprecedented (5 + 2)-cycloaddition reaction of ortho -hydroxyethyl phenol and internal alkyne was developed. This Rh( iii )-catalyzed reaction provided benzoxepine derivatives which have very high biological significance. A wide range of ortho -hydroxyethyl phenols and internal alkynes were studied to provide the benzoxepines in high yields. The Rh( iii )-catalyzed annulation reaction of ortho -hydroxyethyl phenols and internal alkynes provides benzoxepine derivatives.