Sulfur insertion reaction

Since the first report of the sulfur-addition reaction to 1,1-dithio complexes (156), a number of structural studies have verified the originally proposed ring expansion of the MS2C ring following this reaction. In addition, mechanistic studies on the sulfur insertion reaction and electronic spectral studies of the perthiocarboxylate Ni(II) complexes have been reported. 

Preparative Methods the title compound can be prepared by reaction of (R)-2-[l-(dimethylamino)ethyl]phenyllithium with elemental sulfur (eq 1). A solution of pure (R)-2-[l-(dimethyl-amino)ethyl]phenyllithium in THF is slowly added at —50°C to a suspension of a stoichiometric amount of freshly sublimed sulfur. The solution is warmed to room temperature and quenched with an equimolar amount of a 10 M aqueous HCl solution. All volatiles are evaporated at reduced pressure and the residue is sublimed at 120 °C in vacuo (0.1 mmHg). The nitrogen-functionalized derivatives (R)-2-[l-(l-pyrrolidinyl) ethyljbenzenethiol and (R)-2-[l-(l-piperidinyl)ethyl]benzen-ethioP may be prepared in a similar way. It should be noted that reaction with MesSiCl instead of HCl after the sulfur insertion reaction affords the corresponding trimethylsilyl thio ether, which also is a valuable catalyst precursor. ... 

This reaction is analogous to the sulfur insertion reaction involved in biotin biosynthesis, and LipA and BioB show significant sequence similarity [145,146]. 8-Mercapto-octanoic acid and 6-mercapto-octanoic acid are intermediates... 

BioB and lipoate synthase represent a group of radical SAM enzymes that catalyze sulfur insertion reactions (Figure 4) and were among the group of enzymes identified early on to utilize iron-sulfur clusters and SAM in... 

In exchange reactions of disulfides and polysulfides and in sulfur insertion reactions... 

Scheme 19 Synthesis by the insertion reaction of sulfur atoms into the M-C and M-M bond...

McKervey and Ye have developed chiral sulfur-containing dirhodium car-boxylates that have been subsequently employed as catalysts for asymmetric intramolecular C-H insertion reactions of y-alkoxy-ot-diazo-p-keto esters. These reactions produced the corresponding ci -2,5-disubstituted-3(2H)-furanones with diastereoselectivities of up to 47% de. Moreover, when a chiral y-alkoxy-a-diazo-p-keto ester containing the menthyl group as a chiral auxiliary was combined with rhodium(II) benzenesulfoneprolinate catalyst, a considerable diastereoselectivity enhancement was achieved with the de value being more than 60% (Scheme 10.74). 

Sulfur insertion into thiols RSH to give symmetrical trisulfides in high purity is easily accomplished by diimidazolylsulfide (reaction conditions hexane, 0-25 °C, 0.5-2 h).[34]... 

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

The CJS insertion reaction was suppressed completely upon catalytic decomposition of diazoketones 361, where the sulfur substituent was alkyl, acyl or thioacyl. It is presumed that sulfonium ylides occur as intermediates which give cepham (or cephem) derivatives in all cases270,343) rather than products of a Stevens rearrangement. 

The S02 molecule has unshared pairs of electrons on both the sulfur and oxygen atoms. As a result, it forms numerous complexes with transitions metals in which it is known to attach in several ways. These include bonding through the sulfur atom, through an oxygen atom, by both oxygen atoms, and various bridging schemes. In most cases, the complexes involve soft metals in low oxidation states. Another important reaction of sulfur dioxide is known as the insertion reaction, in which it is placed... 

The thiazyl cation is used for the preparation of other important S-N compounds. For example, the insertion reactions with S4N4 or SC12 produce [S5N5]"1" or the acyclic [C1SNSC1]+ cation,62 respectively, and the reaction with sulfur gives [S2N]+ salts. 

Insertion Reactions of Transition Metal-Carbon o--Bonded Compounds II. Sulfur Dioxide and Other Molecules, 12, 31... 

Sulfur trioxide, at —10°C in OFCI3 solution, undergoes an insertion reaction to yield the orange solid (mp = 27°C) CIO2OSO2F (254). The same compound was also obtained (296) in the absence of a solvent ... 

Recently, however, Tokitoh and co-workers " °° reported a versatile reactivity of Tbt-substituted plumbylenes 182a-d, that is, insertion reactions with alkyl halides, diphenyl dichalcogenides, bromine abstraction from carbon tetrabro-mide, and sulfurization with elemental sulfur as shown in Scheme 14.83. 

Reactions other than Lewis acid-base associations/dissociations are frequently observed wit donor molecules, leading notably to solvolysis, oxygen or sulfur abstraction, insertion reaction and carbon-carbon coupling reactions. The tendency to form metal-element multiple bonds i remarkable in this respect the activation of dinitrogen by tantalum or niobium is unique. Th formation and chemistry of constrained reactive metallacycles open another promisin fast-developing area, on the frontier with organometallic chemistry. 

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