Sulfur transfer agents

Compounds containing the iV-thiosulfinylamino group (R—N=S=S) have been reported recently.85 "88 The aryl compounds are rather unstable purple oils which show promise as sulfur transfer agents, although few definitive examples have yet been reported.87... 

The use of other phosphorus-sulfur reagents for heterocyclic synthesis appears rare. It would be interesting to investigate in more detail the reaction of compounds, such as the phosphine sulfides, with organic substrates. Triphenylphosphine sulfide is an effective sulfur transfer agent, as it converts oxiranes into thiiranes in good yield. The reaction proceeds with retention of configuration.128... 

Treatment of 1,2-dihydroxyethane or higher 1,2-diols with S2CI2 <65JOC2696>, or with the sulfur transfer agent, thiobis(benzimidazole) <80CC825>, afforded 1,3,2-dioxathiolane 2-thiones. 

Ru, Os and Re nitrido complexes require more reactive sulfur transfer agents, such as S2C12 or SC12, which can also serve to oxidize the metal if used in excess (equations 58-60). 

It is worth noting, that when 2,2,4,4-tetrabromo-l,3-dithietane 73 was treated with dimethylthioformamide (DMTF), the S-atom from this sulfur-transfer agent replaced the two geminal bromine atoms on C-2 and the 4,4-dibromo-l,3-dithietane-2-thione 74 was formed in good yield (Equation 11) <2002SUL115>. 

Two efficient syntheses have been reported for the parent 1,2,5,6-tetrathiocane (108). Treatment of 1,2-ethanethiol with TEA and carbon tetrachloride reportedly gave (108) in 85% yield <89Ml 926-01 >. Benzyltriethylammonium tetrathiomolybdate, (BnNEt3)2MoS4, a stable sulfur transfer agent, reacted with 1,2-dibromoethane to give (108) in 58% yield <94J0C1354>. 

Without additional reagents N,N -Thiobisphthalimide as sulfur-transfer agent 2,l>3-S,N,N-Heterocyclics... 

As regards the modification of intemucleosidic links, bis(deoxynucleosidyl)-trimethylsilyl phosphites 190 can be converted to phosphorofluoridates 191 by the use of S02C1F,230 and dibenzoyltetrasulfide has been advocated as a rapid sulfur transfer agent in the synthesis of nucleoside phosphorothioates, being used to prepare a phosphorothioate after each cycle of a phosphoramidite synthesis.231 Oxidation of intemucleosidic H-phosphonothioates (2 -deoxy series) with iodine in aqueous acetonitrile in the presence of trimethylamine gives... 

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