DIALKYLATIVE CYCLIZATION REACTIONS OF 3-(PHENYLTHIO)-3-SULFOLENES

3-(Phenylthio)-3-sulfolene (4) underwent bridged dialkylative cyclization with 2-methylene-1,3-diiodopropane to give the bridged bicyclic 3-sulfolene 23, and spirodialkylation with 1,4-diiodobutane and 1,5-diiodopentane to give the spiro bicyclic 3-sulfolenes 15 as the major product. The reaction of 4 with 1,3-diiodopropane led to the fused bicyclic 2-sulfolene 12. 3-(Phenylthio)-3-sulfolenes bearing an omega-iodoalkyl group at the C-2 position gave the fused bicyclic 2-sulfolenes 28 and/or the spiro bicyclic 3-sulfolene 29 depending on the chain length.