Further Information
Literature
Related Reactions
Mitsunobu
Reaction
Staudinger Reaction
Synthesis of alkyl
bromides
Synthesis of alkyl
chlorides
Appel Reaction
The
reaction of triphenylphosphine and tetrahalomethanes (CCl4,
CBr4) with alcohols is a ready method to convert an alcohol
to the corresponding alkyl halide under mild conditions. The yields are
normally high.
This reaction is somewhat similar to the Mitsunobu Reaction, where the combination of a phosphine, a diazo
compound as a coupling reagent, and a nucleophile are used to invert the
stereochemistry of an alcohol or displace it.
Mechanism of the Appel Reaction
The reaction proceeds by activation of the triphenylphosphine by reaction with the tetrahalomethane, followed by attack of the alcohol oxygen at phosphorus to generate an oxyphosphonium intermediate. The oxygen is then transformed into a leaving group, and an SN2 displacement by halide takes place, proceeding with inversion of configuration if the carbon is asymmetric.
Recent Literature
ROMPgel-Supported Triphenylphosphine with Potential Application in Parallel
Synthesis
E. Arstad, A. G. M. Barrett, B. T. Hopkins, J.
Koebberling, Org. Lett., 2002, 1975-1977.
Conversion of alcohols to bromides using a fluorous phosphine
L. Desmaris, N. Percina, L. Cottier, D. Sinou,
Tetrahedron Lett., 2003, 44, 7589-7591.
The facile preparation of alkenyl metathesis synthons
T. W. Baughman, J. C. Sworen, K. B. Wagener, Tetrahedron, 2004, 60, 10943-10948.
