Sulfur-substituted 1, 3-butadienes are useful reagents in organic synthesis. We now report two general methods for the regio-and stereoselective synthesis of substituted 2-(phenylthio)- 1, 3-butadienes 4 and 5. 3-(Phenylthio)-3-sulfolenes 2 can be specifically alkylated at C5 under basic conditions. Extrusion of sulfur dioxide by lithium aluminum hydride then gives the dienes 4. On the other hand 2-substituted 3-s~ dfolenes 11 can be converted to the 3- ...
