Ethyltriphenylphosphonium bromide

Figure 19.1 Synthetic scheme for example pheromone components. Abbreviations al and a2 = Wittig-Homer condensations with triethyl 2-phosphonopropionate and triethyl 2-phosphonobutyrate, respectively b = reduction of ester with lithium aluminum hydride c = partial oxidation of alcohol with manganese dioxide to aldehyde dl and d2 = Wittig condensations with ethyltriphenylphosphonium bromide and propyltriphenylphosphonium bromide, respectively e = condensation with dimethylhydrazone phosphonate reagent f = hydrolysis under acidic conditions. Compound numbers are as in Table 19.1.

Corey and co-workers " found that when powdered sodium hydride is stirred into excess dimethyl sulfoxide under nitrogen at 65-70° hydrogen is evolved with formation of a solution of the highly reactive sodium methylsulfinyl methylide (1). This salt reacts with ethyltriphenylphosphonium bromide at room temperature to form the Wittig reagent (2), as shown by its rapid reaction with benzophenone to form 1,1-diphenylpropene-l (3). The strongly basic character of methylsulfinyl... 

Preparation. A mixture of -bromophenetole, triphenylphosphine, and phenol as solvent is stirred at 90° for 48 hrs., and the crystalline white phenoxy-ethyltriphenylphosphonium bromide is precipitated with ether and refluxed with... 

Prepared in solution by treatment of ethyltriphenylphosphonium bromide (Aldrich) with base (usually /i-butyllithium).1 It has also been prepared in high yield by use of dimsylsodium as base and DMSO as solvent.2... 

The equilibrium established between methylenetriphenylphosphorane and ethyltriphenylphosphonium bromide in THF has been investigated by quenching with benzaldehyde. 

TSE at 290°C / torque rheometry / HDT / capillary rheometry / SEM / FTIR / mechanical properties / ethyltriphenylphosphonium bromide catalyst (0-0.02 parts)... 

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