Copper(I)-Promoted Synthesis of Highly Substituted and Functionalized Tetrahydrothiophenes

Copper(I)-promoted 5-exo halogen-atom-transfer radical cyclization of 2,2,2-trihaloethylallyl sulfides gave highly functionalized tetrahydrothiophenes in good to high yields. Stereochemical aspects of the diastereomeric mixtures of products formed under different reaction conditions were evaluated, and single-crystal diffraction analysis and 2D NMR spectroscopic analysis were carried out. The synthetic application of α-acetoxy tetrahydrothiophenes in the preparation of a dihydrothiophene has also been demonstrated.