2- Aminophosphinic acid esters

Aminophosphinic acid esters. NaNHg added at -33° with stirring to ethyl benzylpropylphosphinate and N-benzylidene-p-toluidine in abs. ether, and after 4 hrs. treated with 7%-HCl at the same temp. -> ethyl (2-p-toluidino-l,2-diphenyl-ethyl)propylphosphinate. Y 81%. F. e. s. M. Kirilov, J. Petrova, and K. PetkanSin, B. 104, 173 (1971) -aminocarboxylic acids s. A. Dobrev and C. Ivanov, B. 104, 981. 

Nucleophilic addition of methyl- or phenylphosphite n -butyl- esters to oxo-imine salts, generated by nitrone alkylation of triethyloxoniumtetrafluoro borate (Meerwein salt), leads to a-aminophosphinic acid esters (Scheme 2.201) (691). 

Phosphonic acid amide esters P-Aminophosphinic acid esters 10... 

The hydrolysis of tervalent phosphorus acid derivatives with two P—C bonds leads to secondary phosphine oxides (50) and with one P—C bond to phosphonus acid derivatives (51). Chlorophosphines react rapidly with water, but aminophosphines, phosphinites and phosphonites often survive a short wash with aqueous NaHC03, an effective way to remove contaminating ammonium salts in the crude products. However, aminophosphines with small substituents, e.g. dimethylaminodimethylphosphine, aryl phosphinites and phosphonites and trimethylsilyl phosphinites and phosphonites are hydrolysed too quickly for such a treatment. The hydrolyses are catalysed by acids (the hydrolyses of phosphinites and phosphonites are also catalysed by OH ) and are much faster than hydrolyses of the corresponding phosphoryl compounds [up to a factor of 10 for acid-catalysed hydrolysis of (MeO)3P compared with (MeO)3P=0 ]. Dialkyl phosphonites are rapidly hydrolysed to the monoalkyl esters (51, X = OR) in weakly acidic water, whereas hydrolyses to phosphonous acids require reflux with strong acid or base, e.g. equation 131 Bis-(dialkylamino) phosphines may also be partially hydrolysed to phosphonous acid amides (51, X = NR2). Tervalent phosphorus acid derivatives with hydrogen sulphide give secondary phosphine sulphides or phosphonodithious acids, e.g. equation 156 . ... 

Aminophosphines. The synthesis and use of aminophosphines as ligands have been reviewed. Raeemie ehlorophosphines of the type R R PCl have been shown to react stereoselectively with chiral amines (1-phenylethylamine or aminoacid esters) in the presence of triethylamine to give the diastereomerically enriched aminophosphines (137), which were isolated as diastereomerically pure crystalhne borane complexes. This approach has also been used in the synthesis of chiral t-butylphenylphosphine oxide, via the acid hydrolysis of an intermediate chiral aminophosphine. Among other new mon-oaminophosphines prepared by treatment of primary or secondary amines with ehlorophosphines in the presence of a base are the adenine derivatives (138), the phosphinoalkylaminophosphines (139), " the aminophosphine-phosphine... 

Hii reported an aminophosphine ligand similar to Amphos [118]. This ligand is prepared in four steps, starting from N-methylaniline and bromoacetic acid ethyl ester. An elevated temperature of 110°C was required to achieve aminations of aryl bromides with secondary amines. Surprisingly, the order of reactivity is reported to be reversed to that usually encountered for palladium-catalyzed couplings, and consequently electron-deficient aryl bromides were aminated in lower yields than the corresponding electron-rich electrophiles. The ligand metal ratio was identified as one of the key parameters for the reaction. 

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