ISSN:
0947-3440
Keywords:
α-Phosphanyl ketones
;
2-Phosphanyl alcohols
;
α-Phosphanyl hydrazones
;
Asymmetric α-phosphanylation
;
Phosphane-borane adducts
;
Asymmetric synthesis
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An efficient, highly enantioselective methodology for the synthesis of α-phosphanyl ketones 7 and 2-phosphanyl alcohols 12 and 13, important hemilable ligands for enantioselective homogeneous catalysis and chiral building blocks in general, has been developed. The key step of this first enantio-selective synthesis of α-phosphanyl ketones is the diastereo-selective phosphanylation of SAMP hydrazones 2 to produce α-phosphanyl hydrazones, isolated as the more stable borane adducts 6. Subsequent ozonolysis afforded α-phosphanyl ketones 7. The enantioselective synthesis of 2-phosphanyl alcohols 12 and 13 has been accomplished by two fundamentally different procedures: the phosphanylation of unsubstituted chiral aldehyde hydrazones 9 and the alkylation of α-diphenylphopshanyl acetaldehyde SAMP hydrazone 10. After separation of the minor diastereomer, the borane-protected α-phosphanyl aldehyde hydrazones 11 were converted to unprotected 2-phosphanyl alcohols 13 by ozonolysis, reduction and removal of the borane group. The absolute configuration of the functionalized phosphanes was determined by X-ray analysis, NOE experiments or polarimetry.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199719970212
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