Triphenylvinylphosphonium bromide

The addition of trimethyltinlithium to triphenylvinylphosphonium bromide (Scheme 3) produced a new type of metallo-ylide (7), which on addition to cyclohexanone gave (8), containing a very nucleophilic double bond, which in the... 

It has also been reported that some 4-substimted-5(47/)-oxazolones 166 undergo Michael addition to triphenylvinylphosphonium bromide to give the corresponding 4,4-disubstituted-5(47/)-oxazolones 167 from which ring opening... 

Irradiation of 3-phenyl-2H-azirines (2) with triphenylvinylphosphonium bromide (3) in acetonitrile forms 2H-indoles (4) (equation 3)29. The probable mechanism of formation of 4 leads, via benzonitrile ylide and 1,3-dipolar cycloaddition, to the C C double bond of the vinylphosphonium bromide via the assumed intermediate (5). 

Three l-hydroxy-3-phenylpyrroles (46) were formed (72JOC1561) in 26-44% yields, instead of the anticipated 6//-oxazines, when the corresponding E-oximes (44) were treated successively with one equivalent of sodium hydride in dimethylformamide (DMF) followed by triphenylvinylphosphonium bromide Z-benzil oxime gave no pyrrole. The cyclization probably proceeds via cyclization to the N-oxide 45 and tautomerism to the 1-hydroxypyrrole. 

Additions to Vinylphosphonium Salts. Two reports of the reaction of -mercaptoketones with triphenylvinylphosphonium bromide in the presence of base to yield 2,5-dihydrothiophens (86) have appeared. -... 

The reaction of triphenylvinylphosphonium bromide with substituted diazoacetophenones leads only to the formation of the 3-substituted pyrazoles (88), as outlined in Scheme 5, presumably because of the high acidity of the 5-proton in the intermediate (89). ... 

Triphenylvinylphosphonium bromide undergoes cydoaddition with a variety of dienes to give phosphonium salts, e.g. (90). ... 

The formation of a stable 1,2-oxaphospholan from the sodium salt of benzoin and triphenylvinylphosphonium bromide has been extended to substituted vinylphosphonium salts, diastereoisomers being obtained in some cases. 

On irradiation in acetonitrile, 3-phenyl-2ff-azirines of type 138 react with triphenylvinylphosphonium bromide 128 to form 2H-pyrroles 141 (Scheme 29), presiunably via the photochemically generated dipoles 139 and the products 140 of a [2+3]-cycloaddition reaction between 138 and 139 [79], Derivatives of 141 bearing an a-H rearrange to the pyrroles 142. 

Related Reagents. Triphenylvinylphosphonium Bromide l-(Methylthiovinyl)triphenylphosphoniumChloride l-(Methyl-thiovinyl)triphenylphosphonium Tetrafiuoroborate Diphenyl (l-phenylthiovmyl)phosphine Oxide (+ )-(5)-Diethoxyphos-phorylvinyl />Tolyl Sulfoxide. ... 

Scheme 54 Tandem copper-NHC-catalysed ECA of Grignard reagents to a-substituted cyclic enone/enolate trapping with triphenylvinylphosphonium bromide 32 by Alexakis [88]...

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