Methylation of Simple Unsaturated Hydrocarbons by Dimethyl Sulfoxide

Sequential Double Olefination of 2‐(Arylmethylidene)‐2‐phosphonoacetonitrile with Dimsyl Lithium and Aldehydes: A Domino Route to Densely Substituted 1,3‐Butadienes

“…Although, Michael addition [19] of carbon nucleophiles, stabilized by positively charged S, As and Te is well known, dimsylate anion (methylsulfinyl carbanion) has not received much attention over the years especially as a substitute for sulfonium or sulfoxonium ylides. [20] Earlier reports [21][22][23] on the reaction of dimsylate ion with electrophiles (carbonyls, olefins) provided products like sulfonium or sulfoxonium ylides produced with those electrophiles. But, the reactions were performed under harsh conditions.…”

Generation of semidione and semitrione radical anions in dimethyl sulfoxide

“…These results together with the similarities of the splitting constants of XLII with those of the aromatic protons of XIX, XX, and XXI suggest that XLII is CgH^C(0~) = C(0*)0t-Bu. It is known that alkoxlde bases are capable of removing a proton from DMSO (7,12,17,22), yet in the above results there is no indication of the formation of I. When I is formed by the reaction of sodium hydride with DMSO and the resultant solution allowed to cool, and then mixed with DPPT in DMSO the spectrum shown in Figure 10 is obtained.…”

“…Clearly I is a capable methylating reagent for some aromatic hydrocarbons (19,21). When anthracene was methylated in DMSO with _t-BuOK as the base, the yield of 9-niethylanthracene was cut almost in half (22).…”

Reactions of organic sulfoxides

“…The methylsulfinylcarbanion forms adducts with ketones (9,13^14,23, 24), aldehydes (13^16, 25), olefins (23,24,26^27), alkynes (28), benzyne (13j16), epoxides (29,30)j and esters (10,15,16). Certain aromatic com pounds have been methylated by attack of the methylsulfinylcarbanion followed by base catalyzed elimination of methylsulfinie acid (27,31)-Beta-keto sulfoxides were not prepared until 1963^ although the analogous beta-keto sulfides and beta-keto sulfones had been known for twenty years (32)(33)(34). Thé direct oxidation of p-keto sulfides to sulfox ides has not been accomplished.…”