Dithio and thiono esters .62. Reactions of alkanedithioic acid dianions with iodine, sulfur, and tin compounds

The monoanion of the alkanedithioic acid 1a is oxidized with hypervalent iodine compounds to form the 1,2-dithiine 6, the monoanion of 1b yields the 1,2,4-trithiolane 7 and the dianions 2b, c furnish the 1,2,4,5-tetrathianes 3b, c. With diphenyltin or dimethyltin dichlorides 8 the monoanions of 1b, c afford the monothioacyl or bisthioacyl organotin sulfides 19a-c or 11a, b respectively. When treated with lithium hexamethyldisilazane, 10b undergoes an intramolecular cyclization to the 1,3,2-dithiastannetane 9b; 10a is deprotonated by triethylamine to the 1,3,5-trithia-2-stanninane 13. The dianion 2c reacts with diphenyltin dichloride 8 to yield the 1,3,2-dithiastannetane 9d, with dimethyltin dichloride the 1,2,4-trithiolane 16 is formed. 9d is cleaved by thionyl chloride, sulfur dichloride, and disulfur dichloride to give a complex mixture of the 1,2,4,5-tetrathiane 3c and the cyclic polysulfides 1,2,3,4,5,6-hexathiepane 18, 1,2,3,5,6,7-hexathiocane 19 and the 1,2,3,5,6-pentathiepane 20 in varying amounts. Reaction of the dianion 2b with thionyl chloride leads to the formation of the 1,2,4,5-tetrathiane 3b as main product; byproducts are cyclic polysulfides, the 1,2,3,5,6-pentathiepane 21 and the 1,2,3,4,5,6-hexathiepane 22.