Halophosphines synthesis

Data from this laboratory and others8,9,10 indicate that the general procedure outlined for the synthesis of F2PX compounds may be extended to the synthesis of the oxy derivatives of pentavalent phosphorus such as F2C1P0 and Cl2FPO, but the detailed directions are not given here. The mixed oxyhalides of phosphorus, like the corresponding mixed halophosphines, have not been obtained easily in pure form from complex reaction mixtures.11,12... 

Chromophores based on aryl moieties can be easily grafted on to halophosphines via simple nucleophilic substitutions, as illustrated by the synthesis of 114 (Scheme 4.34). As a result, numerous phosphines bearing extended jt-conjugated substituents have been prepared. The aim of this section is not to give a comprehensive account of all derivatives that have been synthesized, but rather to illustrate how phosphorus fragments can be used either to influence or to organize the Jt-conjugated systems, with special emphasis upon fluorescence and NLO properties. 

The complexes [OsNXs] " (X = Cl, Br) and [OsNX4] (X = Cl, Br, I) are very useful starting materials for the synthesis of a wide range of substituted Os and Os halophosphine complexes, and species incorporating phos-phineiminato, Os=N-PR3, functionalities. The electrochemical oxidation of cis- and irani -[Os(terpy)(Cl)2NH3](PF6) and [Os(terpy)(bpy)(NH3)](PF6)2 is metal based at low pH. However, at high pH proton loss and oxidation of boimd ammonia occurs to yield either [Os(terpy)(Cl)2(N)](PF6) via a four-electron process or [Os(terpy)(bpy)(NO)](PF6)3 by a six-electron process. ... 

By far the most important type of reaction displayed by halophosphines is nucleophilic substitution. This is pivotal to the preparation of many other three-coordinate compounds containing either solely P—C, P—O, P—N bonds, or mixed combinations. These reactions are often exothermic and frequently carried out at low temperatures. For the synthesis of phosphorus(III) compounds containing a P—O or P—N bond it is often necessary to add a base (triethylamine or pyridine are frequently used) to capture the hydrogen halide eliminated from these condensation reactions. In the case of P—C bond formation, a variety of routes are possible using various carbon-derived nucleophiles. 

Asymmetric synthesis utilizing chiral auxiliaries represents the most effective method for the synthesis of chiral organophosphorus compounds. During the last few years this method has seen significant development [17-20]. Nucleophilic displacement at the phosphoms atom is one of the most popular and efficient methods for the preparation of enantiopure P-chiral compounds. At present, the most commonly used are chiral secondary alcohols/halophosphines [12,13,15,17],... 

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