Enzymes in organic chemistry — 5: First and chemo-enzymatic synthesis of α-aminooxyphosphonic acids of high enantiomeric excess
作者:Martina Drescher、Friedrich Hammerschmidt
DOI:10.1016/s0040-4020(97)00174-9
日期:1997.3
alpha-Acyloxyphosphonates (+/-)-5a and (+/-)-5b, derived from 3-phenylpropionaldehyde and acetaldehyde. were involved by lipase-catalyzed enantioselective hydrolysis. Three of the four chiral, non-racemic alpha-hydroxyphosphonates obtained had 99% ee. the fourth 91%. They were transformed chemically into alpha-aminooxyphosphonic acids. (C) 1997 Elsevier Science Ltd.
Determination of absolute configuration of α-hydroxyphosphonates by 31P NMR spectroscopy of corresponding mosher esters
作者:Friedrich Hammerschmidt、Li Yong-Fu
DOI:10.1016/s0040-4020(01)81758-0
日期:1994.8
(R)-MTPA esters of alpha-hydroxyphosphonates 1a-h of known absolute configuration were prepared and their P-31 NMR spectra were recorded. The chemical shifts of the P-31 signals of the derivatized (S)-alcohols are consistently downfield relative to the signals of the corresponding (R)-alcohols. A variety of racemic and diastereomeric alpha-hydroxyphosphonates 1i-o and their (R)-MTPA esters were prepared. The P-31 chemical shift differences are large enough to securely assign absolute configurations to alpha-hydroxyphosphonates.
Hammerschmidt Friedrich, Li Yong-Fu, Tetrahedron, 50 (1994) N 34, S 10253-10264