Alkylphosphinates

As stated in Chaps. 2 and 3, 1-substituted alkylphosphonates and salts of alkylphosphonates, such as lC-22 (clacyfos, HW02), lG-21 (HWS), and IIJ-24 were found to display promising h bicidal activity and good selectivity for development as a potential herbicide. These results also encouraged us for further exploration on alkylphosphinates based on these alkylphosphonates. Therefore, we are very interested to design novel 1-(substituted phenoxyacetoxy) alkylphosphinates and examine their herbicidal activity. 

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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]. 

COi is another molecule which reacts with conjugated dienes[10,95,96], COt undergoes cyclization with butadiene to give the five- and six-membered lactones 101. 102. and 103, accompanied by the carboxylic esters 104 and 105[97.98], Alkylphosphines such as tricyclohcxyl- and triisopropylphosphine are recommended as ligands. MeCN is a good solvent[99],... 

Other typical alkylphosphines that can be prepared through phosphine chemistry are monoisobutylphosphine [4023-52-3] trioctylphosphine [4731-53-7] monocyclohexylphosphiue [822-68-4] dicyclohexylphosphiue [829-84-5] and triethylphosphiue [554-70-1]. 

A mixture of (C H ) , TiCl, and AlCl is useful for polymerizing C —olefins (85). The dimerization of propylene is accompHshed by using catalysts such as Ni(PR2)4 (86). Alkylphosphines such as / fZ-butylphosphine [2501-94-2] have been proposed as a substitute for high purity phosphine in the production of the semiconductor gallium phosphide (87). 

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. 

Figure 2.67 Syntheses of rhodium complexes of bulky di(f-butyl)alkylphosphines.

In the presence of a base such as l,4-diazabicyclo[2.2.2]octane (DABCO) or tri-alkylphosphines, conjugated carbonyl compounds such as esters and amides add to aldehydes via the a-carbon to give a-alkenyl-P-hydroxy esters or amides. This sequence is called the Baylis-Hillman reaction and a simple example is... 

Several t-alkylphosphines have been oxidized by aqueous alkali, resulting in the evolution of hydrogen gas. The only requirement for reduction appears to be the solubility of the phosphine in aqueous alkali... 

In accord with the current interest in stereochemistry at phosphorus a number of optical studies on phosphonous derivatives have been carried out. Benschop and his group have achieved a partial resolution of alkyl alkylphosphinates (133) by stereospecific inclusion in cycloamyloses. Optical purities in the range 20—80% were obtained. 

Yoshida and Otsuka found that platinum(O) complexes [PtLj] (26) (a L = PEtj b L = P Prj) and rhodium hydrido complexes such as [RhHLj] (L = P Prs 33, PEts), [RhiHidr-NJlPCyslJ (34), tram-[RhH(N2)(PPh Bu2)J, and [RhH(P Bu3)J, all of which carry electron-donating alkylphosphine ligands, can catalyze the water gas shift reaction under fairly mild conditions (100-150°C CO 20 kg/cm ) (Eq. 6.32) [23, 60]. Among these complexes, [RhH(P Pr3)3] (33) was the most active catalyst precursor. Several complexes were isolated from or detected in the reaction mixture... 

Sterically demanding, water-soluble alkylphosphines 6.10 and 6.11 as ligands have been found to have a high activity for the Suzuki coupling of aryl bromides in aqueous solvents (Eq. 6.35).115 Turnover numbers up to 734,000 mmol/mmol Pd have been achieved under such conditions. Glucosamine-based phosphines were found to be efficient ligands for Suzuki cross-coupling reactions in water.116... 

Similar additions also occurred on vinylphosphine oxides. When the optically active vinylphosphine oxide was used, P-chiral alkylphosphine oxide was obtained with retention of the configuration (Eq. 10.27)60... 

Secondary lower-alkylphosphines readily ignite in air [1] preparative precautions are detailed [2,3],... 

Contact with oxygen at 25°C/0.5 bar causes ignition of the phosphine. See related alkylphosphines... 

Di[bis(trifluoromethyl)phosphido]mercury N [(F3C)2P]2Hg Grobe, J. et al., Angew. Chem. (Intern. Ed.), 1972, 11, 1098 It ignites in air. See related alkylphosphines See other MERCURY compounds C4Fi2HgP2... 

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