THE CHEMISTRY OF 1,2-DITHIINS - SYNTHESIS OF 1,2-DITHIIN AND 3,6-DISUBSTITUTED 1,2-DITHIINS

An efficient, generally applicable method for the synthesis of a varie ty of 3,6-disubstituted 1,2-dithiins has been established. The method involves the regio- and stereoselective 1,4-bis-addition of atkylthiol s to 1,4-disubstituted 1,3-butadiyne at room temperature in DMF in the presence of a catalytic amount of KOH. Subsequent reductive removal o f the thiol-protecting group with Li/liq NH3/THF at -78-degrees-C foll owed by oxidative ring closure of the resulting dilithium dithioenolat es with I2/KI provides the red-colored 1,2-dithiins.