Thiocarbonate protonation

Sulfur as Heteroatom. Thiols and sulfides are protonated on sulfur in superacid media and give mono- and dialkylsulfonium ions, respectively.136 Thio-carboxylic acids, 5-alkyl esters, thioesters, dithioesters, and thiocarbonates in similar media also form stable protonated ions541,647 such as cations 348-353. 

Minkwitz and co-workers have recently obtained the X-ray crystal structure of protonated thiocarbonic acid, protonated (9,5-dimethyl dithiocarbonate, and protonated dimethyl trithiocarbonate. Protonated thiocarbonic acid 354 has C—S bond lengths of 1.683-1.708 A.662 The small differences imply a nonequal distribution of the positive charge over the S atoms. All hydrogen atoms have trans positions and they are... 

Studies of the reactions of O-ethyl S-(2,4,6-trinitrophenyl)thiocarbonate (16) and its dithio analogue with hydroxide ions in water show the initial rapid formation of 3-hydroxy adducts which may ionize by proton loss. Slower irreversible reactions are observed resulting from attack by hydroxide at the 1-position or the carbonyl carbon atom. The spirocyclic cr-adduct (17) has been observed during reactions of )V-picryl-)V,iV -di(2-furoyl)hydrazine with base eventually aminodenitration of the 2-nitro group yields a benzoxadiazine derivative. ... 

S isomerisation when exposed to methyl iodide and proton sponge. The gluco derivative (79), for example, was converted to the rearranged product (80). Others, e.g.. the arabino compound (81), were stable under identical conditions. Attempts to reduce the thiocarbonate (79) by treatment with tributyltin radicals furnished instead the glycal (82). ... 

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