Alkylphosphines containing

Organophosphorus compounds. Phosphorus-carbon bond fonnation takes place by the reaction of various phosphorus compounds containing a P—H bond with halides or tritlates. Alkylaryl- or alkenylalkylphosphinates are prepared from alkylphosphinate[638]. The optically active isopropyl alkenyl-methylphosphinate 778 is prepared from isopropyl methylphosphinate with retention[639]. The monoaryl and symmetrical and asymmetric diarylphosphi-nates 780, 781, and 782 are prepared by the reaction of the unstable methyl phosphinate 779 with different amounts of aryl iodides. Tnmethyl orthoformate is added to stabilize the methyl phosphinate[640]. 

Phosphorus containing poly(maleimide-amines) were synthesized from N,N -bisdichloromaleimido-3,3 -diphenyl alkylphosphine oxides and aromatic diamines or piperazine [144]. The polymers prepared from piperazine are soluble in DMF, DM AC, DMSO, etc., but have poor thermal stability and flame retardancy. 

Second-generation Catalysts Containing Sterically Hindered Alkylphosphines 382... 

The fluorous alkylphosphines 2 [8, 12] and 3 [8, 13], containing one or two perfluoroalkyl tails, respectively, have also been prepared. Partition coefficients of the chiral fluorous monophosphines 3a-b were found to be lower than the values measured for the corresponding phosphines 1, which contain one extra perfluoroalkyl tail [13], In addition, fluorous phosphinites, phosphonites and phosphites 4a-e and diphosphonite 5 have become available [8, 14]. 

The previously problematic second substitution after the /ram-sclcclivc monoalkynylation can now be achieved selectively (>98% selective with retention) and in high yields. The use of alkylzincs and most critically alkylphosphines such as (f-Bu)3P, as ligands, was the key to the development of the satisfactory procedure (Scheme 47)85. Conventional arylphosphines, such as PPh3, I I P and DPEphos, as well as the use of Ni catalysts in conjunction with alkylmetals containing Mg106 and Zn led to low yields and/or extensive and synthetically unattractive stereoisomerization85. 

Phosphonium salts manufactured by the above metathesis route will typically contain a few ppm of halogen anion. In many cases, this may be irrelevant, but if a totally halogen-free salt is required, they can readily be prepared in a simple one-pot procedure by heating a tertiary alkylphosphine with a tosylate, sulfate, or phosphate ester [51,59,60[. Examples are triisobutyl(methyl)phosphonium tosylate (CYPHOS IL 106),tributyl(methyl)phosphoniummethylsulfate (CYPHOS IL 108), and tributyl(ethyl)phosphonium diethylphosphate (CYPHOS IL 169). 

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