ISSN:
0009-2940
Keywords:
o-Phosphanylphenols
;
P,O hybrid ligands
;
P asymmetry
;
C,O-dilithium reagents
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reactions of C,O-dilithium reagents 1 (M = M′ = Li) or C,O-lithium-sodium reagents 1 (M = Li, M′ = Na) with chlorophosphanes afford C,O-disubstitution products 2 or phosphanylphenolates 3 which are treated subsequently with ClSiMe3 to give 4-methyl- and bulky 4,6-di-tert-butyl substituted o-phosphanylphenol silyl ethers 4. These were applied for the preparation of the corresponding o-phosphanylphenols 5, mainly P-asymmetric derivatives. Limitations and side reactions by use of 1 in the above synthesis are discussed. Acid-base properties, pH-dependent solubility in water/hexane, and substitution reactions at oxygen and phosphorus of selected representatives of 5 are reported. An example for the separation of enantiomers by esterification with (1S)-(—)-camphanic acid chloride is given. IR studies revealed intramolecular P-H—O bonds and 2J(PC) the preferred trans arrangement of the phenoxy group in solution. In the solid state, inter- and intramolecular P-H—O bonds were detected by X-ray structure analysis. The trans arrangement of the phenoxy group is preserved. Because of steric hindrance, the O substituents are tilted towards the phosphorus atom and thus induce large through-space coupling constants. The P-Sn distance of 336.9 pm in the bulky substituted O—SnMe3 moiety 8h is however too large for the formation of genuine intramolecular coordination. The versatility of o-hydroxyarylphosphanes and objectives of further studies are shown by preliminary results on complex formation and applications of these phosphanes in catalysis.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19961291223
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