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35.2.1.5.2.7 Variation 7: Reaction of Alcohols with Triphenylphosphine–Bromine

DOI: 10.1055/sos-SD-035-00308

Braun, M.Science of Synthesis, (200735331.

The reaction of alcohols with triphenylphosphinebromine is advantageous compared with the traditional reagents hydrobromic acid and phosphorus tribromide because it delivers one and only one bromide that serves as the nucleophile. In addition, it avoids strongly acidic conditions so that it is a more suitable reagent for the reaction of acid-sensitive substrates and the preparation of acid-sensitive products. The general mechanism for the formation of bromoalkanes from alcohols is outlined in Scheme 13. It involves first a rapid formation of an alkoxyphosphonium bromide that undergoes a slow decomposition, yielding the desired alkyl bromide with concomitant formation of triphenylphosphine oxide.[‌51‌]

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