Bismuthonium ylides reactions

The reaction of the same bismuthonium ylide with isothiocyanates in the presence of a copper(H) catalyst afforded the sulfur-incorporated spiro-cyclic compound as the main product, in addition to a small amount of carbon-carbon bond formed products (Scheme 12) [28],... 

R = Php-Tol, 4-CIC6H4, hexyl, Ph C02CH2 Scheme 11 Reaction of bismuthonium ylide with alkynes... 

Scheme 12 Reaction of bismuthonium ylide with isothiocyanates...

Stabilized bismuthonium ylides have also been made from compounds having reactive methylene groups, CH2CXY, X, Y = RCO or RSO2, either by making their sodium salts and letting the latter react with dichlorotriphenylbismuth, or by reaction with triphenyl-bismuth oxide 1 181. 

A number of triphenylbismuthonium diacylylides and also the diphenylsulphonylylide undergo transylidation when treated with dimethyl sulphide in the presence of copper(I) chloride in benzene at room temperature, giving the corresponding dimethylsulphonium ylides no such reaction took place with diphenyl sulphide Some of these bismuthonium ylides reacted with triphenylarsine or triphenylphosphine and were converted thereby into arsonium or phosphonium ylides they did not react with triphenylstibine L The conversion of the diacetylylide into the 4,4-dimethyl-2,6-dioxocyclohexylide as mentioned in Section IX.A should also be noted. 

By contrast, the sodium salt of acetylacetone (31) was reported to react with triphenylbismuth dichloride in THE to lead to an unstable bismuthonium ylide (37). It was formed nearly quantitatively after 1 hour at 0-5°C, but was not isolated. Addition of triethylamine and methanesulfonyl chloride led to the isolation of a l,3-oxathiole-3,3-dioxide derivative (38) in 65% yield. On the other hand, this bismuthonium ylide (37) afforded the mono-C-phenylated product, 3-phenylacetylacetone (35), on standing at room temperature. However, the precise experimental conditions and the yields of the latter reaction were not reported. " ... 

The reaction of dimedone (39) with tetraphenylbismuthonium derivatives and BTMG gave the a,a-diphenyl derivative (40). But when dimedone (39) was treated with triphenylbismuth carbonate, an ylide (41) was obtainedP This ylide was later isolated as a stable crystalline compound. This ylide (41) can also be prepared by reaction of the sodium salt of dimedone either with triphenylbismuth dichloride or with triphenylbismuth oxide. Similarly, Meldrum s acid gave the corresponding bismuthonium ylide with triphenylbismuth carbonate and with triphenylbismuth dichloride.3 36 uch ylides can also be made by decomposition of the appropriate dicarbonyl diazonium derivative in the presence of triphenylbismuthane catalysed by bis(hexafluoroacetylacetonato)copper (II) 37 These ylides react with aldehydes to give cyclopropanes, dihydrofurans and a,p-unsaturated carbonyl... 

The 1,3-oxathiole 3,3-dioxides (331) are formed by treatment of a silyl enol ether (330) with an a-halosulfonyl bromide followed by dbn (Equation (56)) <84JOC3664> and the similar compounds (333) can be prepared by reaction of the stabilized bismuthonium ylides (332) with a sulfene (Equation (57)) <89cci749>. 

The reaction of triphenylbismuth carbonate with cyclic 1,3-dicarbonyl compounds, such as dimedone and Meldrum s acid, gives highly stabilized triphenylbismuthonium ylides (Section 3.5.1). Moderately stabilized acyclic bismuthonium ylides can be prepared from triphenylbismuth dichloride and a 1,3-diketone or a 1,3-disulfone in the presence of a suitable base. A similar base-promoted reaction of triphenylbismuth dihalides with Al-sulfonylamines or amides has been used for the preparation of stabilized bismuthine imides bearing the Af-sulfonyl or Af-acyl moiety (Section 3.6.1). 

In 1967, Lloyd et al. claimed the first synthesis of a bismuthonium ylide by heating triphenylbismuthine and diazotetraphenylcyclopentadiene at 140°C. However, experimental details confirming the product are not available [67CC1042, 88JCS(P2)1829], Thermogravimetric analysis of the reaction shows that the carbene, cyclopentadienylidene, is formed at the initial step [72CC912]. 

A stable bismuthonium ylide is formed by the reaction between triphenyl-bismuth carbonate and dimedone [85JCS(P1)2667]. The cyclic a,a -dioxo structure is likely to be the main origin of high stability. 

Copper(I)-catalyzed reaction of a stabilized bismuthonium ylide with phenylacetylene... 

All the characteristic reactions of stabilized and moderately stabilized bismuthonium ylides are described in Section 5.4.3.3 with reaction schemes. 

Scheme 5.33. Typical reactions of a stabilized bismuthonium ylide derived from dimedone.

The carbenes or carbenoids can be generated in a variety of ways. It is not always clear whether the reaction is concerted or stepwise and whether the carbene behaves as an electrophilic, nucleophilic or radical species. For instance, a carbenoid generated from bismuthonium ylide (19) in the presence of copper(I) chloride would behave as a triplet and add as a radical to a terminal alkyne" (equation 17). The dicarbonyl structure and the absence of reaction with methyl propionate to a furane might well indicate electrophilic character of this carbene. 

Carbon functional groups, attachment to polysilanes, 3, 585 Carbon-heteroatom bond formation via antimony(III) compounds, 9, 428 via antimony(V) compounds, 9, 432 via bismuth(III) compounds characteristics, 9, 440 with copper catalysts, 9, 442 non-catalyzed reactions, 9, 443 with bismuth(V) compounds, 9, 450 with bismuthonium salts, 9, 449 with bismuth ylides, 9, 450 Carbon-heteroatom ligands in tetraosmium clusters, 6, 967 in tetraruthenium clusters, 6, 960... 

The latter ylide has also been made in a transylidation reaction from the corresponding bismuthonium diacetylylide and dimedone in the presence of triethylamine no reaction took place in the absence of the amine ... 

In a few cases this reaction gives ylides of PhaP and PhsAs, albeit in relatively low yield. In combination with isothiocyanates, some bismuth ylides yield complicated addition products, although the fate of the bismuth atom in these reactions is not determined. Likewise, bismuthonium compounds are finding a growing utility in organic synthesis d. 

Carbon-carbon bond forming reactions based on bismuthonium salts and ylides... 

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