Alkylphosphonates Alkylphosphonic diesters

N.m.r. and i.r. spectroscopic studies on the nature of the carbanionic species from alkylphosphonic diesters, and the relevance... 

Whereas alkylphosphonic diesters react readily with lithium or organomagnesium reagents with the formation of the metallated phosphonate carbanions, the reactions between such esters and the metals themselves result, by contrast, in dealkylation of the ester groups involving both C-0 and P-0 cleavage traces of unsaturated hydrocarbons, even including alkynes and aromatics, are thought to be formed by radical-induced reactions. 

Maier and others have carried out Michaelis-Arbuzov reactions between alkyl bis(chloromethyl)phosphinates (41) and trialkyl phosphites to give alkyl bis[(dialkoxy-phosphinyl)methyl]phosphinates (42), and with alkylphosphonous diesters to give bis[(alkoxyalkylphosphinyl)methyl]phosphinic esters (43). Analogous reactions with bis-... 

Yet another way to obtain a 1 -monohalogenated alkylphosphonic diester is based on the application of the Wadsworth-Emmons adaptation of the Wittig reaction (Scheme 10). Here, the anion from tetraisopropyl (fluoromethyl)bisphosphonate reacts with a carbonyl compound to give the (l-fluoroalk-l-enyl)phosphonic esters 126 as an E-Z mixture (80-95 20-5) hydrogenolysis of these mixtures yields (l-fluoroalkyl)phosphonic esters. In a review of the literature the authors pointed out the widely different results experienced by other workers in their attempts to alkylate carbanions derived from fluorinated alkylphosphonic diesters and, as a result of their own work, advocated the use of alkyl triflates, which appear to react with lithiated carbanions very quickly and cleanly. 

Alkylation of dialkylphosphorous salts by dialkyl phosphites and by phos-phonic diesters has been mentioned above (page 729). The latter reaction can be used for nearly quantitative preparation of salts of alkylphosphonic monoesters, by converting the dialkyl phosphite into its sodium salt and heating this in a sealed tube with a catalytic amount of a phosphonic diester containing the same alkyl group.329 Further, when heated alone, sodium dialkyl phosphites afford, according to the conditions, sodium alkylphosphonates or disodium phosphonates and dialkyl phosphonates.330... 

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