How reaction conditions may influence the regioselectivity in the synthesis of 2,3-dihydro-1,4-benzoxathiine derivatives

The exploration of different reaction conditions aiming to obtain both 2,3-dihydro-1,4-benzoxathiine-2-yl derivatives and 2,3-dihydro-1,4-benzoxathiine-3-yl ones is here reported. The treatment of 1,2-mercaptophenol with an organic base and a specific 2-bromo acrylate results in a solvent- and substrate- dependent exclusive solvation of O- and S- anions, thus managing the regioselectivity.