Yb(OTf)3 catalyzed [3+2] annulations of D-A cyclopropanes with β-oxodithioesters: a regioselective synthesis of tetrahydrothiophenes

A new route to prepare tetrahydrothiophene derivatives from D-A cyclopropanes and beta-oxodithioesters catalyzed by Yb(OTf)(3) is reported. This is the first example using beta-oxodithioesters as dipolarophiles to react with D-A cyclopropanes. The method exhibits good regioselectivity.