Carbon sulfides insertion reactions

Exxon s Flexsorb SE solvents achieve high hydrogen sulfide selectivity by virtue of their molecular structure. These solvents are sterically hindered secondary amines. A bulky molecule is used to shield the available hydrogen radical on the nitrogen atom and prevent the insertion of carbon dioxide. The reaction with hydrogen sulfide is not sensitive to the amine s structure, so the steric hinderance affords higher hydrogen sulfide selectivity. 

Carbon disulfide also reacts with tin amides, such as Me3SnNMc2, to give the insertion products . Tin alkoxides react similarly to give the 1 1 adducts. For example, reaction of bistributyltin oxide 103 with carbon disulfide affords bis(tributyltin)sulflde 105 with elimination of carbonyl sulfide . The reaction involves the insertion product 104 as an intermediate. 

The treatment of various sulfides with Phi = NTs in the presence of cuprous triflate leads to the corresponding N-tosylsulfimides (N-tosylsulfilimines) 21 [30]. The presence of the chiral bis(oxazoline) ligand 22 in the reaction medium results in coordination of the copper(III)-nitrene intermediate, L Cu(III) = NTs, and enables the enantioselective production of 21 (Scheme 12). Similar copper-catalyzed reactions of allylic sulfides with Phi = NTs lead to formal insertion of the NTs group into the carbon-sulfur bond of the substrates, and proceed via a [2,3]-rearrangement with allylic inversion, to give sulfonamides 23 [30]. 

Eventually we formed carbonyls in the liquid phase by redox disproportionation of nickel and cobalt derivatives of organic thioacids. In the reaction between nickel(II) dithiobenzoate and carbon monoxide in the presence of HS ion we assumed the formation of a sulfur-bridged nickel(IV) complex (VII, 32). More recent investigations (84), however, have shown that half the nickel appears as a monomeric nickel(II) complex of the same empirical formulation, formed by insertion of a sulfur atom in the dithio ligand, the other half of the nickel being reduced to nickel(O) by the sulfide. 

Electron paramagnetic resonance measurements have confirmed the existence of polysulfenyl radicals in liquid sulfur which competitively abstract hydrogen or which react by insertion or addition to give carbon sulfur bonds (20, 21). Hydrogen abstraction and subsequent hydrogen sulfide formation occurs predominantly above 160°C and must be avoided by reducing the mixing temperature. At temperatures below 160°C the prevalent reaction is believed to be the sulfur addition into the asphalt molecule (18,19, 22,23). 

Sigmatropic rearrangement. Transpositional rearrangement with one-carbon insertion of allylic sulfides occurs in the reaction with Me SiCHNj that is catalyzed by FeCl2(dppe). 

A series of heterodinuclear late organotransition metal complexes (dppe)RPt-M(C0)4 (M = Mn, Re) show the unexpected regio- and seteroselective desulfurization of thiiranes controlled by the ancillary alkyl ligand (Scheme 3.69) [133]. Reaction of the methyl complex, (dppe)MePt-M(CO)4 with cis- and trans-2-butene sulfide results in the insertion of the thiirane into the Pt-M bond followed by the CO insertion into the carbon-M bond and coordination of the S atom to the... 

The catalytic potential of transition metal sulfides for abiotic carbon fixation was assayed. It was found that at 2000 bar and 250 °C, the sulfides of iron, cobalt, nickel, and zinc promote the hydrocarboxylation reaction via carbonyl insertion at a metal sulfide bound alkyl group. The results of the study support the hypothesis that transition metal sulfides may have provided useful catalytic functionality for geochemical carbon fixation in a prebiotic world [141]. 

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