Dithiocarboxylates oxidation

Thione-S-oxides react regiospecifically with allyl and benzylsilanes in the presence of a stoichiometric amount of tetra-n-butylammonium fluoride to produce allyl and benzyl sulphoxides [8], cf. the analogous fluoride initiated reaction of thio-ketones and dithiocarboxylic esters with silanes [9, 10]. The yields of sulphoxides... 

The reaction between [MoCl4(NCPr)2] and dithiocarboxylic acids is a general route to the preparation of eight-coordinate [Mo(S2CR)4] complexes.168 The crystal structure of [Mo(S2CPh)4] reveals these compounds to be isostructural with the dithiocarbamates, with a dodecahedral coordination around the molybdenum and average Mo—S distances of 2.475(1) and 2.543(1) A to the two different sulfur sites.170 Cyclic voltammetry has shown that in [Mo(acda)4] (Hacda = 2-aminocyclopent-l-ene-l-dithiocarboxylic acid) the Mo can be reversibly oxidized and reversibly reduced in one-electron processes.171... 

The silver(I) dithiocarboxylates are frequently associated, to form clusters, such as [Ag(C2SCi0H7)Py]4 and [AgS2CCPh3]6, or polymers, such as [Ag2(S2CPh)2]x. The formation of Cu1 dithiocarboxylates from Cu11 salts frequently results in the oxidation of the ligand to perthiocarboxylates, and cluster complexes, e.g., [CuSS(S)CC10H7]4 and Cu4(S2CPh)2[SS(S) CPh]2(Py)2 are obtained.361... 

A new and facile synthetic method to prepare complexes with Ti-S bonds is based on the oxidation of the low-valent titanium sandwich complex CpT CyHy) with dithiocarboxylic acid to give the Ti(iv) dithioacetate CpTi(S2CMe)3 (Scheme 421). The compound has been fully characterized including X-ray crystallography. It consists of discrete seven-coordinate molecules with a slightly distorted pentagonal-bipyramidal coordination... 

Dihydrotetrazines (340), which can easily be oxidized to 1,2,4,5-tetrazines, can be formed by dimerization of thiohydrazides (337) or amidrazones (338). The ring closure of hydrazidines (339) in a [5 + 1] fashion proceeds well with activated carboxylic acid derivatives such as imidates (341), orthocarboxylates (342) or dithiocarboxylates (343). The [4 + 2] procedure is found in the transformation of 1,3,4-oxadiazoles (346) or 1,4-dichloroazines (345) with hydrazine. Finally diazoalkanes (344) can be dimerized in a [3 - - 3] manner under the influence of a base the dimerization of diazoacetic ester is an early example, leading to 3,6-tetrazinedicarboxylate (48), which is frequently used in (4 -I- 2) cycloaddition reactions with inverse electron demand. Nitrile imines, reactive intermediates which are formed from many precursors, can dimerize in a [3 -I- 3] fashion to form 1,3,4,6-tetrasubstituted 1,4-dihydrotetrazines. These reactions are summarized in Scheme 57. 

In 1994, successful isolations of various alkyl and aryl selenocarboxylic acids [14] enabled them to undergo exact reactions. Reactions of selenocarboxylic acids with dicyclohexylcarbodiimide (DCC) yield the corresponding diacyl selenides 25 and selenourea 26 quantitatively (Scheme 15) [14], as in reactions of thio- [44] and dithiocarboxylic acids [45,46]. In air,selenocarboxylic acids are immediately oxidized to afford the corresponding diacyl diselenides [13, 14]. Also, thio- and dithio-carboxylic acids readily react with aryl isocyanates to give acyl carbamoyl [47,48] and thioacyl carbamoyl sulfides [49, 50], respectively. 

Many dithiocarboxylate compounds of sulfur have been reported. Bis(thioacyl) disulfides 100, dimers of dithiocarboxylate ligands, are easily synthesized by oxidative dimerization of the corresponding dithiocarboxylic acids (Scheme 26) [151-154]. Their reactivities toward cycloaddition reactions and S-S bond cleavage have been investigated [155-157]. Bis(thioacyl) trisulfides 101 and tetrasulfides 102 are also prepared by treating the dithiocarboxylic acid with SCI2 and S2CI2, respectively [135]. 

On the one hand, the reaction of imidazolium-2-dithiocarboxylate 111 with bromine gives the corresponding cationic thioacylsulfenyl bromide 112 [173]. On the other hand, treatment of 111 with an equimolar amount of iodine gives the charge transfer complex 113. Two iodine atoms and a thiolate sulfur atom are arranged in almost a linear fashion in 113. Further treatment of 113 with an excess amount of iodine causes oxidative coupling, affording the dicationic disulfide 114 (Scheme 27). 

---