3- Bromopropyltriphenylphosphonium

A) Preparation of 3-Bromopropyltriphenylphosphonium Bromide Triphenylphosphine, 1.0 kg, and 770 grams of 1,3-dibromopropane are dissolved In 2.0 liters of xylene and the solution is stirred under a nitrogen atmosphere at 130°C. After 20 hours the mixture is cooled, and the crystalline product, which precipitates, is collected and washed with 20 liters of benzene. After drying in vacuo the product weighs 1,578 grams, MP 229°-230°C titration for bromide ion Found, T7.1% calculated, 17.2%. 

The dye-sensitized (eosin) photooxygenation at —50 °C of alkylidenecyclopropanes 85, easily available by the Wittig reaction of 3-bromopropyltriphenylphosphonium ylide44 and suitable ketones, gave the hydroperoxides 86, which were reduced in situ by an equivalent of triphenylphosphine 45 to 1-alkenylcyclopropanols 87 in good yields. When PPh3 was replaced by pyridine (5 %) 86 rearranged exclusively... 

Prepared in 97% yield by the reaction of 3-bromopropyltriphenylphosphonium bromide (Aldrich) with sodium acetate in 4 1 acetone-water. 

Cyclopropyltriphenylphosphonium bromide is conveniently prepared from 3-bromopropyltriphenylphosphonium bromide (71) by treatment with equimolar sodium ethoxide in absolute ethanol. ... 

The reagent (2) has been prepared in several ways, but the most convenient method involves intramolecular cyclization of 3-bromopropyltriphenylphosphonium bromide (1, available front Aldrich) by sodium hydride in THF.1... 

Bromopropyltriphenylphosphonium bromide was obtained in quantitative yield by-heating equimolar amounts of 1,3-dibromopropane and triphenylphosphane in xylene at 130 °C for 16 h. 

Bromopropyltriphenylphosphonium bromide added at room temp, under Ng to a suspension of 2 equivalents of a 53%-NaH-mineral oil dispersion in 1,2-di-methoxyethane, a little ethanol added, stirred 6 hrs. at 60-70°, benzophenone... 

An improved preparation of cyclopropyltriphenylphosphonium bromide by 1,3-elimination from co-bromopropyltriphenylphosphonium bromide with dilute aqueous sodium hydroxide has also been reported. ... 

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