[2] Electron-rich sources of phosphorus such as phosphites, phosphonites, and phosphinites may undergo nucleophilic addition to carbon atoms in simple carbonyl compounds.
When fully esterified phosphites are used (Abramov reaction), neutralization of the resulting tetrahedral intermediate usually occurs via the transfer of an alkyl or silyl group from an oxygen attached to phosphorus to the newly created alkoxide center.
In the presence of two equivalents of aldehyde cyclic phosphoranes 1 (equation 3) predominate, but these can be easily hydrolyzed to give the corresponding hydroxy phosphonates.
[8] However, asymmetric induction and selective direct addition (for conjugated carbonyl compounds) can be achieved in the presence of chiral amine bases.
Selective silyl group transfer occurs in mixed reagents, and cleavage of the resulting silicon-oxygen bonds can often be accomplished hydrolytically, providing access to α-hydroxy derivatives.
Alkylation of α-siloxy products provides a convenient route to otherwise difficult to access α-alkoxy phosphorus compounds.
In one interesting application, addition to ketenes gives products identical to the Arbuzov reaction of acid halides.
[13] Primary amines can be produced only after acidic hydrolysis of an intermediate tert-butylamine;[14] the use of unsubstituted imines requires very harsh conditions and gives low yields.