Direct Regioselective [3 + 2]-Cyclization Reactions of Ambivalent Electrophilic/Nucleophilic β‑Chlorovinyl Dithianes: Access to Cyclopentene Derivatives

The highly regioselective and operationally straightforward [3 + 2] cyclizations of β-chlorovinyl dithianes with α,β-unsaturated carbonyl compounds have been developed. This protocol provides direct access to highly functionalized cyclopentenes with perfect chemo- and regioselectivities under extremely mild reaction conditions. In particular, the unprecedented cyclization allows for the selective preparation of hydroxylated cyclopentenes.