2-Nitrobenzyltriphenylphosphonium

An example of such an impact is the Wittig reaction. For the formation of double bonds from 2-nitrobenzyltriphenylphosphonium bromide and methyl 4-formyl-benzoate, it was determined that the ratio of cis and trans products (Z/F ratio) can be changed by simply adjusting the voltages in an electroosmotic-flow driven chip... 

Organic synthesis 78 [OS 78] 2-Nitrobenzyltriphenylphosphonium bromide and four aldehydes... 

The testing of 2-nitrobenzyltriphenylphosphonium bromide and methyl 4-formylbenzoate and four other aldehydes, 3-benzyloxybenzaldehyde, 2-naphthaldehyde, 5-nitrothiophene-2-carboxaldehyde and 4-[3-dimethylamino)propoxy]benzaldehyde, has been reported [13]. 

P 58] Another protocol focused on continuous contacting of the two reactant solutions. Again, flow was fed by electroosmotic means [13]. A 0.01 M methanol solution of 2-nitrobenzyltriphenylphosphonium bromide was used a 0.02 M methanol solution for methyl 4-formylbenzoate with sodium methoxide (0.015 M) was used. Volumes of 80 pi of both solutions were set in the respective reservoirs on the chip and 40 pi of methanol in the collection reservoir. A voltage of 400 V was applied for both feed lines. The reactions were carried out at room temperature and run for 20 min. 

The 1 1 ratio was realized by plug insertion instead of continuous feed as in the 2 1 case. One injection per minute of 2-nitrobenzyltriphenylphosphonium bromide was made for a duration of 30 s into a continuous stream of the aldehyde solution at 400 V [13]. 

A soln. of p-nitrobenzyltriphenylphosphonium fluoride prepared from the chloride with Amberlite IRA 400 (F ) anion exchanger in methanol treated with p-nitro-benzaldehyde and abs. acetonitrile, heated with distillation of the solvents until the b. p. of acetonitrile is reached, then refluxed 24 hrs. -> 4,4 -dinitrostilbene. Y 84%. - Addition of a base is not necessary because the fluoride ion is strongly nucleophilic in polar aprotic solvents it functions as base and attacks its own cation. F. e. s. G. P. Schiemenz, J. Becker, and J. Stockigt, B. 103, 2077 (1970). 

Styrenes. A suspension of m-nitrobenzyltriphenylphosphonium bromide in aq. 40%-formalin added slowly with stirring to aq. 10%-Na-carbonate soln. -> m-nitrostyrene. Y 90%. F. e. with isolation of the intermediate phosphorane s. M. Butcher, R. J. Mathews, and S. Middleton, Australian J. Chem. 26, 2067 (1973). 

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