Science of Synthesis

Braun, M., Science of Synthesis, (2007) 35, 331.

The reaction of alcohols with triphenylphosphine–bromine 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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‌Meeeee 88‌ Meeeeeeeeee ee Meeee Meeeeeee eeee Meeeeeee eeee Meeeeeeeeeeeeeeeee–Meeeeee[‌88‌–‌88‌]

‌Meeeeeeeeee 88‌

M8	Meeeeee	Meeee (%)	Mee
MM8e-Me	MMM	88	[‌88‌]
8-eeeeeeeeee	eeeeeeee	88	[‌88‌]
	eeeeeeee, MM8Me8	88	[‌88‌]
(MM8)8M≡MM	MeMM	88	[‌88‌]
(M)-(MM8)8MM=MM(MM8)8Me	MeMM	88	[‌88‌]
MMMe(MM8)8Me	MM8Me8	88	[‌88‌]
MM8MM=MMMe	MeMM	88–88	[‌88‌]

e (+)-eee-8-Meeeeeeeeeeeeee eeeeee eeee (+)-eeee-eeeeeeeee-8-ee.

Meeeeeeeeeee Meeeeeeee

(+)-eee-8-Meeeeeeeeeeeee (‌88‌, M8 = 8-Meeeeeeee); Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeeeee ee e eeeeee eeeeeeee ee eee eeee, eeeeee eeeeeeeee, eeeee, eee eeee. Meeeee eeeeeee eeeeee eeeeee eee eeeeeee eeeee ee eeeeeee eeee eeee eee eeee.

Me8M (88.8 e, 888 eeee) eee (+)-eeee-eeeeeeeee-8-ee {[α]M +8.88 (e 8.88, MMMe8); 88.8 e, 888 eeee} eeee eeeee ee eeeeeeee (888 eM) eeeee eeeeeeee. Mee eeeeeee eee eeeeeee eeeee e eeeeeeeeeee eeee eeeeee. Me eee eeeeee eee Me8 (88.8 e, 888 eeee) eeeeeeeee ee eeee eeeeeeee (88 eM) eee eeeee ee eee eeeeeeeeeee eee eeeeeeeeee eeeeeee 88 eee 88°M; eee eeeeeeeeeeee eeee-eeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeee eeeee ee eeeeeeeeeee eeee eeeee eee eeeeeeee eee eeeeeee. M eee eeeeeeee ee 888 Me eee eeeeeee eee eee eeee eee eeeeee eeeeee ee eeeee eee eee MMe eeeeeee; eee eeee eee eeee eeeeeeeee eeeee eee ee eee eeeeeee eee eeeeeee eee eeee eeeeeeeee (eee eeeee eee eeeeeeeeee eeeeeee eee eeeeeeeee eee eee eeeeeeee eee eeeeee ee e eee eee/eeeeeee eeee). Mee eeeeeeeeee eee eeeee ee eee eeeee (8 M) eee eee eeeeeee eeeee eee eeeeeeeee. Mee eeeeeee eeeee eee eeeeeeeee eeee 88-eM eeeeeeee ee MMMe8 eee eeeeeeeee; eee eeeeeeee eeeeeee eeeeeeee eeee eeeeee eeee ee Me8MM8 (888 eM), eeeee eee ee eeee eeeeeeeee eeee e eeeee eeeeee ee MMMe8. Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee M8M, eeeee (MeMM8), eee eeeeeeeeeeee eeeeeee e Meee eeeeee eeeeee eeee eeeee eeeeeee; eeeee: 88.8 e (88%); ee 88–88.8°M/8 eMe; eM88 8.8888; [α]M 8.88 (e 8.88, MMMe8).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8e, 888.