Methyltriphenylphosphonium bromide

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Methyltriphenylphosphonium bromide
Ph3PCH3+Br-.png
Names
Preferred IUPAC name
Methyltri(phenyl)phosphanium bromide
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
EC Number
  • 217-218-9
UNII
  • InChI=1S/C19H18P.BrH/c1-20(17-11-5-2-6-12-17,18-13-7-3-8-14-18)19-15-9-4-10-16-19;/h2-16H,1H3;1H/q+1;/p-1
    Key: LSEFCHWGJNHZNT-UHFFFAOYSA-M
  • C[P+](C1=CC=CC=C1)(C2=CC=CC=C2)C3=CC=CC=C3.[Br-]
Properties
C19H18BrP
Molar mass 357.231 g·mol−1
Appearance white solid
Hazards
GHS labelling:
GHS06: ToxicGHS07: Exclamation markGHS09: Environmental hazard
Danger
H300, H301, H302, H312, H315, H319, H332, H411
P261, P264, P270, P271, P273, P280, P301+P310, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Methyltriphenylphosphonium bromide is the organophosphorus compound with the formula [(C6H5)3PCH3]Br. It is the bromide salt of a phosphonium cation. It is a white salt that is soluble in polar organic solvents.

Synthesis and reactions[edit]

Methyltriphenylphosphonium bromide is produced by treating triphenylphosphine with methyl bromide:[1]

Ph3P + CH3Br → Ph3PCH3Br

Methyltriphenylphosphonium bromide is the principal precursor to methylenetriphenylphosphorane, a useful methylenating reagent. This conversion is achieved by treating methyltriphenylphosphonium bromide with strong base.[2]

Ph3PCH3Br + BuLi → Ph3PCH2 + LiBr + BuH

References[edit]

  1. ^ Wittig, Georg; Schoellkopf, U. (1960). "Methylenecyclohexane". Organic Syntheses. 40: 66. doi:10.15227/orgsyn.040.0066.
  2. ^ Fitjer, Lutz; Quabeck, Ulrike (1985). "The Wittig Reaction Using Potassium-tert-butoxide High Yield Methylenations of Sterically Hindered Ketones". Synthetic Communications. 15 (10): 855–864. doi:10.1080/00397918508063883.