Thiones oxidation

A selective reaction was also observed in the heterocyclic series with 1,3-thiazole-5-(4ff)-thione oxides and alkyllithiums [107]. A more sluggish reaction was observed with Grignard reagents. 

Dithiole-2-thione (176) reacts with (V,A/-dichIorosulfonamides to give the 1,3-dithiol-2-ylidenesulfonamides (177) and (178) as well as the 1,3-dithiole-2-thione oxide (179). It has been established that the primary step in these reactions is nucleophilic attack of the exocyclic sulfur of the l,3-dithiole-2-thione on the chlorine of the amide to produce an ion pair which can react in three ways to furnish the l,3-dithiol-2-ylidenesulfonamides (79LA689). 

Sundetmeyer, W. Perhalogenated sulfines (thione oxides) and sulfenes (thione dioxides) their s3mthesis and synthetic potential. Synthesis 1988, (5), 349-359. 

An analysis of the electronic structure in these complexes using Resonance Raman, EPR and Density Functional Theory (DFT) calculations provide evidence for tautomers depicted in Scheme 2.41 as an admixture of a thione-thiolate structure, which can be considered to result from electron density distributed into the quinoxaline structure from partial thiolate to thione oxidation (Scheme 2.41). ... 

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