Carbon-phosphorus bond formation substitution

The lithium salt of a substituted cyclopentadienyl anion has been used in reaction with phosphorus trichloride for carbon-phosphorus bond formation.70 The resultant simple displacement product ultimately undergoes dimerization and loss of four (from the dimer) equivalents of HC1 (Equation 4.25). 

The use of an electron-rich trivalent phosphorus center for addition to or substitution at an electrophilic site is a long-established approach to the formation of carbon-phosphorus bonds. The classical studies of the Michaelis-Arbuzov, Michaelis-Becker, Abramov, Pudovik, and related reactions and their mechanisms and synthetic utilities have been thoroughly reviewed. In this chapter, we present only a brief introduction to these reactions and provide several examples of their more facile uses from the older literature. More attention is given to relatively recent developments regarding such reactions that are seen as improvements in their general utility. 

Ionic dissociation of carbon-carbon a-bonds in hydrocarbons and the formation of authentic hydrocarbon salts, 30, 173 Ionization potentials, 4, 31 Ion-pairing effects in carbanion reactions, 15, 153 Ions, organic, charge density-NMR chemical shift correlations, 11,125 Isomerization, permutational, of pentavalent phosphorus compounds, 9, 25 Isotope effects, hydrogen, in aromatic substitution reactions, 2,163... 

By far the most important type of reaction displayed by halophosphines is nucleophilic substitution. This is pivotal to the preparation of many other three-coordinate compounds containing either solely P—C, P—O, P—N bonds, or mixed combinations. These reactions are often exothermic and frequently carried out at low temperatures. For the synthesis of phosphorus(III) compounds containing a P—O or P—N bond it is often necessary to add a base (triethylamine or pyridine are frequently used) to capture the hydrogen halide eliminated from these condensation reactions. In the case of P—C bond formation, a variety of routes are possible using various carbon-derived nucleophiles. 

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