Polyphosphine synthesis

I am indebted to the U.S. Air Force Office of Scientific Research for support of the research on polyphosphine synthesis. In addition the work on the synthesis and catalytic activity of polyphosphines containing neomenthyl terminal groups was part of an United States-Hungarian cooperative science project in collaboration with L. Marko of the Veszprem University of Chemical Engineering and funded jointly by the U.S. National Science Foundation (Grant INT-76-20080) and the Hungarian Institute for Cultural Relations. In connection with these projects I acknowledge the skillful experimental collaboration of Pramesh Kapoor, John Cloyd, William Masler, Jozsef Bakos, and Carl Hoff. 

Synthesis of Chiral Polyphosphines from Perfluoroalkyl Phosphinidenes... 

Examples of tridentate phosphines include the synthesis of tris(diphenylphosphino)ethene (101) in 51% yield by the base-catalyzed addition of Ph2PH to the 1,2-disubstituted phosphine Ph2PCCPPh2 (Equation (27)).217 This protocol has also been used in the preparation of various polyphosphines using (Ph2P)2C=CH2 and an appropriate P—11 source, again with KOBu1 as base.218,219... 

The synthesis of polyphosphines containing combinations of primary, secondary, and tertiary phosphorus atoms by the base-catalysed addition of P—H across the carbon-carbon double bond of vinyl phosphonates, followed by reduetion with lithium aluminium hydride, has again been described. The preparation of I,2-bis(phosphino)ethane from the bis-phosphonate (17) by reduction with lithium aluminium hydride has been reported in detail. ... 

Baudler s group (and others) continue to make extensive use of alkali-metal polyphosphide reagents in the synthesis of both cyclic " and acyclic polyphosphines. " A wide range of new systems has been described in the past year, and the field as a whole has been reviewed. ... 

King et developed a route to poly(tertiary phosphines) by use of a base-catalyzed addition of a phosphorus-hydrogen bond to the carbon-carbon double bond of various vinylphosphine derivatives the first extensive series of methylated polyphosphines were prepared this way. The synthesis of unsymmetrical diphosphines of the type i 2PCH2CH2P(CH3)2 involves addition of a P-H bond to CH2=CHP(S)(CH3)2 via potassium tert-bwioxxdQ catalysis, followed by desulfurization with LiAlH4 in boiling dioxane (i.e.. Equations 10,11). 

Although the synthesis of 24 was not done under high dilution conditions, the 18% yield could probably be increased significantly by using Kyba s apparatus.Synthesis of other complicated crown-ether-type polyphosphine molecules can be expected in the near future. 

Whereas many tri- and tetra-dentate combinations of nitrogen, oxygen, and sulfur donors have been accomplished via the template effect for two decades, syntheses of polyphosphine ligands via a template synthesis... 

In a particularly interesting application of the radical- and base-catalyzed synthesis of polyphosphine ligands (Section 3.2.2), Keiter have prepared all five possible nonchelated triphosphine complexes of W(CO)5 (35-39). 

A. Caminade, J.-P. Majoral, and R. Mathieu, Synthesis of polyphosphine and phosphene transition metal complexes, Chem. Revs., 91, 575, 1991. 

Scheme 2.39 Synthesis of a polyether-based dendrimeric polyphosphine of the third generation.

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