Regioselective addition reactions of 3-phenylsulfonyl-2-trifluoromethyl-1,3-butadiene with nucleophiles

Reactions of 3-phenylsulfonyl-2-trifluoromethyl-1,3-butadiene (1) with heteroatom nucleophiles such as pri-amines, pri-alcohols, and thiols afforded the addition products 2, 3, and 5 regioselectively formed via addition of nucleophiles toward double bond attaching phenylsulfonyl group. Cyclization of 2a in 2,2,2-trifluoroethanol at 60 °C for 2 h gave pyrrolidine 4a in good yield. Similarly, compound 1 was also reacted with diethylmalonate in the presence of NaH to give addition product 7 in good yield.