Preparation of S-containing heterocycles via novel reaction patterns of carbon disulfide with 1-lithlobutadienes and 1,4-dilithiobutadienes

Both carbophilic addition and thiophilic addition were involved in the first step intermolecular reaction of 1,4-dilithio-1,33-diene derivatives with carbon disulfide. Thus in situ generated carbophilic addition intermediates and thiophilic addition intermediates underwent a second step intramolecular carbophilic and thiophilic additions. Multiply substituted thiophenes were isolated as the results of cleavage of the C=S double bonds, while thiopyran-2-thiones were produced via cycloaddition reactions. In addition to 1,4-dilithio-1,3-dienes, monolithio reagents also showed interesting reactions with carbon disulfide. Thiophenes were also generated in the reaction of 1-lithio-1,3-dienes with carbon disulfide.