Diphenyl disulfide synthesis

The reaction of 4-lithiodibenzofuran with 0-methylhydroxylamine provides a synthesis of the 4-amino compound, and reaction with iodine leads to the iodo compound. The reactions of 4-lithiodibenzofuran with tributyl borate,diphenyl disulfide, A,A/-dimethylcarbamoyl chloride, and cyanuric chloride have been studied. 

An example of a mild methodology for the synthesis of a-phenylthioketones is given below [214], It makes use of the reagent (1) prepared by Barton [215] from diphenyl disulfide and chloramine T. 

Aromatics for oxidative polymerization usually show high oxidation potentials. The direct oxidation of these monomers by 02 does not proceed because of the large potential gap between the monomers and 02. A novel catalysis by vanadyl complexes is applicable to the synthesis of PPS by the 02-oxidative polymerization of diphenyl disulfide (Eq. 10) [93-103], In the presence of VO(acac)2, the polymerization is accompanied by a quantitative 02 uptake. Dioxygen is essential for the VO-catalyzed oxidative polymerization of diphenyl disulfide. 

Oxidative polymerization of aryl disulfides has been carried out under high dilution conditions for the preparation of cyclic arylene sulfides for synthesizing cyclic arylene sulfide polymers. The readily available diphenyl disulfide and dichloro disulfide with diphenyl sulfide, diphenyl ether, or p-xylene are useful monomers for the synthesis of the corresponding cyclic oligo(thio arylene)s. The reaction scheme is shown in Fig. 30 [101]. 

Tosylamination ofalkenes, The reaction of diphenyl disulfide with chloramine-T in acetone gives, in 91% yield, an adduct of the composition (C6HsSSC6H5)(NTs)2 shown to have the structure (1) by virtue of subsequent reactions with alkenes. Thus it reacts with cyclohexene to give (2), which was reduced by sodium borohydride to (3), whose structure was established by an independent synthesis. 

Although benzylic sulfides will be treated later in a separate section, the synthesis of zearalenone gives the first opportunity to mention their synthetic use. The introduction of sulfur to build the aromatic part of zearalenone was done in two different ways displacement of a benzylic bromide by benzenethiol or reaction of diphenyl disulfide with benzylic carbanion (Scheme 11). 

Trost also found that treatment of these cyclobutanones with sodium methoxide and diphenyl disulfide leads to in situ bisulfenylation and ring cleavage (secosulfenylation). This was applied to the total synthesis of verrucarol, a complex tetrahydrochromanone substituted at the ring junction by a hydroxymethyl substituent. The synthetic strategy twice used the cyclobutanone formation from 1-lithiocyclo-propyl phenyl sulfide and a ketone, followed by the secosulfenylation process and Baeyer-Villiger type rearrangement of cyclobutanone. Only this part of the synthesis is described in Scheme 28. 

A much more stereoselective synthesis of vinylcyclopentanes was obtained when l,l-dihalo-2-vinylcyclopropanes 40 were reacted with electron-deficient alkenes in a process catalyzed by diphenyl disulfide. Cyclization of the intermediate-adduct radicals occurred to give 4-sub-stituted l,l-dihalo-3-vinylcyclopentanes 41 in good yields with excellent diastereoselectivity for the 3,4-CM-isomer. 

The same year, Gerlach described a synthesis of optically active 1 from (/ )- ,3-butanediol (7) (Scheme 1.2). The diastereomeric esters produced from (-) camphorsulfonyl chloride and racemic 1,3-butanediol were fractionally recrystallized and then hydrolized to afford enantiomerically pure 7. Tosylation of the primary alcohol, displacement with sodium iodide, and conversion to the phosphonium salt 8 proceeded in 58% yield. Methyl-8-oxo-octanoate (10), the ozonolysis product of the enol ether of cyclooctanone (9), was subjected to Wittig condensation with the dilithio anion of 8 to give 11 as a mixture of olefin isomers in 32% yield. The ratio, initially 68 32 (E-.Z), was easily enriched further to 83 17 (E Z) by photolysis in the presence of diphenyl disulfide. The synthesis was then completed by hydrolysis of the ester to the seco acid, conversion to the 2-thiopyridyl ester, and silver-mediated ring closure to afford 1 (70%). Gerlach s synthesis, while producing the optically active natural product, still did not address the problem posed by the olefin geometry. 

Zero-valent nickel is especially effective for the cyclization of (7j5(allyl) bromides.2 4 295 Corey used this technique to cyclize 450 to 451. Subsequent photolysis in the presence of diphenyl disulfide (PhSSPh) gave humulene, 452. 94 Wender et al. reported a novel [4+4]-cycloaddition reaction in which two diene moieties are coupled with a nickel(O) catalyst to form eight-membered rings. In Wender s synthesis of asteriscanolide,... 

The syntheses described below for In(EC6H5)3 (E = S, Se) and Sn(ECgH5)4 all involve one-step preparation from the metallic elements and diphenyl disulfide or diselenide. The presence of iodine leads to the formation of InI(EC6H5)2 in the indium/EjfCgHjij system. These methods appear to have many advantages over the metatheses used previously, " and in fact the indium-diphenyl diselenide reactions represent the first synthesis of In(SeC6H5)j and InlfSeCgHjij. 

Ketone synthesis. The anion of (1) can be alkylated in high yield to give (2), but a second alkylation of (2) is difficult. However, the anion of (2), if prepared in the presence of TMEDA, reacts readily with an aldehyde or ketone to form an alcohol (3). When (3) is dissolved in TEA at 20°, diphenyl disulfide leparates and a ketone (4) is obtained from the filtrate (equation I). One advantage )ver the dithiane route is that the hydrolysis step is easier. 

Heterocyclic Synthesis. The reaction of 1,2,3-benzothiadia-zole with PhSH/AIBN in refluxing EtOAc provides a mixture of products including dibenzo[c,e]-o-dithiin (1), thianthrene (2), and 2-(phenylthio)diphenyl disulfide (3). ... 

In 2011, Li s group [116] reported the FeFj (20 mol%)/l2-catalyzed synthesis of 4-chalogen-substituted arylamines by direct thiolation of arene substrates. Diphenyl disulfide was used as the source of the sulfur. 

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