- Diphenylphosphinoyl-mediated synthesis of ketones
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α-Diphenylphosphinoyl ketones are selectively and sequentially alkylated at the α-position. Double lithiation and selective alkylation occurs at the less stabilised γ-position. Dephosphinoylation of the alkylation products gives ketones. Mono-alkylation is selective, highly crystalline intermediates are formed and a one-pot strategy is possible. The method is ideally suited for the preparation of acid-sensitive ketones. The Royal Society of Chemistry 2006.
- Fox, David J.,Pedersen, Daniel Sejer,Warren, Stuart
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p. 3102 - 3107
(2008/02/14)
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- Enantioselective synthesis of α-phosphanyl ketones and 2-phosphanyl alcohols
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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 enantioselective synthesis of α-phosphanyl ketones is the diastereoselective 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. VCH Verlagsgesellschaft mbH, 1997.
- Enders, Dieter,Berg, Thorsten,Raabe, Gerhard,Runsink, Jan
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p. 345 - 363
(2007/10/03)
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