And dimethylsulfonium

Recently, in connection with the use of sulfur ylides in polymerization, Kondo and his coworkers [64] attempted to use diphenylsulfonium bis(methoxycarbo-nyl)methylide (DPSY) (Schemes 27, 29) methylphen-ylsulfonium bis-(methoxycarbonyl)methylide (MPSY) (Scheme 30) and dimethylsulfonium bis (methoxycar-bonyl) methylide (DMSY) (Scheme 31) as photoinitiators for the polymerization of MMA and styrene. They concluded that DPSY and MPSY are effective photoini-... 

Aldehydes and ketones can be converted to epoxides in good yields with the sulfur ylids dimethyloxosulfonium methylid (60) and dimethylsulfonium methylid (61). For most purposes, 60 is the reagent of choice, because 61 is much less... 

Dialkylamino-2,3-dihydrothieno[2,3-6]thiophenes are assumed intermediates as in Scheme 4. Such thiophenes are also formed in the reaction between thione (85) and dimethylsulfonium methylide (Scheme 5). ... 

Challenger, F. and Lui, Y.C., 1950. Elimination of methanethiol and methyl sulfide from methyl-mercapto and dimethylsulfonium compounds by molds. Rec. Trav. Chim. 

Corey, E. J., Chaykovsky, M. Dimethyloxosulfonium methylide and dimethylsulfonium methylide. Formation and application to organic synthesis. J. Am. Chem. Soc. 1965, 87,1353-1364. 

Construction of the suitably substituted geranic acid for making the furan ring has been effected too. For example, Poulter et al. have prepared the substituted geranate 865 by reaction of 4-methyl-3-pentenylcopper with the acetylenic ester 866. The ester 865 then underwent cyclization in the presence of acid to the lactone 867, related to scobinolide (161), and the action of acid on the lactol produced from 867 with diisobutylaluminum hydride gave perillene (849). The lactone 867 has also been prepared by a slightly different method the C9 alcohol 868 was made (in poor yield) from isobutenol and prenyl chloride with butyllithium. The extra carbon atom was introduced by the action of sodium cyanide on the epoxide of 868, and hydrolysis of the cyano group followed by dehydration yielded the lactone 867. The dimethylthioacetal of 867 has been used to synthesize perillene (849). This thioacetal was made from the suitably substituted ketene thioacetal 869 and dimethylsulfonium methylide. Thus the ketene thioacetal 870 (readily prepared from acetone, carbon disulfide, and sodium amylate, followed by methylation °) can be prenylated with lithium... 

The salt is prepared by quaternization of (-)-ephedrine with methyl bromide. Asymmetric oxirane synthesis. Japanese chemists have reported asymmetric synthesis of 2-phenyloxirane from benzaldehyde and dimethylsulfonium methylide generated from tiimethylsulfonium iodide in 50% NaOH with the chiral phase-transfer catalyst (-)-N,N-dimethylephedrinium bromide (1). 

The leaving groups commonly employed in E2 reactions are listed in Table 2.1. As you can see, they are essentially the same as those displaced in nucleophilic substitution reactions (see Part 2), with two exceptions. First, protonated alcohols are not listed as substrates RX in Table 2.1, because they usually react by the El mechanism (as we shall see later) rather than the E2 mechanism. Secondly, the trimethylammonium and dimethylsulfonium groups have limited importance as leaving groups in substitution reactions, although they are particularly important in elimination reactions. In fact, the reaction involving trimethylammonium is known, after its discoverer, as the Hofmann elimination... 

Ylides derived from sulfur rank next in importance to those derived from phosphorus in synthetic utility. The first widely used sulfur ylides were dimethyloxo-sulfonium methylide (4) and dimethylsulfonium methylide (5). The preparations of these compounds are outlined below ... 

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