Five and Six Ring Sulphur Systems

Five and Six Ring Sulphur Systems.—The addition of sulphur dichloride to unsubstituted cyclic polyenes to give bridged bicyclic compounds has been known for a 

Reagents i, NajS,9HjO, DMF ii, HOAc iii, NajS,9H20, tricaprylmethyl-ammonium chloride iv, BH3-THF V, PhlClj, EtsN vi, PhlClj, py or C03H vii, KMn04, MgS04 -30 °C viii. HOAc, 100 

Nakai and his collaborators have shown that bromination of the dithiocarbamate (130) was 100% regiospecific giving (131), which on pyrolysis gave the 1,3- 

Oxidation of dithioketals (135) has given 1,3-dithiolane-l-oxides (136) which on thermolysis gave up to 80% yields of 2,3-dihydro-l,4-dithi-ines (137) via ring expansion. Yet another ring expansion occurred when the 1,3-dithiolane (138) was treated with phosphorus pentoxide in benzene and the tetramethylene 1,4-dithi-ine (139) was obtained. 

Hiratani, and M. Okawara, Bull. Chent. Soc. Japan, 1976, 49, 827. 

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