Enantioselective synthesis of α-amino phosphonic acids by an application of stereoselective opening of homochiral dioxane acetals with triethyl phosphite
摘要:
Stereoselective opening of homochiral acetals (2a-c) with triethyl phosphite was applied to the enantioselective synthesis of phosphono alcohols (1a-c), which were successfully converted to the alpha-amino phosphonic acid diethyl esters (6a-c).
Lipase-catalyzed kinetic resolution of α-hydroxy-H-phosphinates
摘要:
A chiral synthesis of alpha-hydroxy-H-phosphinates was achieved via lipase-catalyzed hydrolysis of acetate precursors. (C) 2004 Elsevier Ltd. All rights reserved.
Enzymes in organic chemistry, part 2: Lipase-catalysed hydrolysis of 1-acyloxy-2-arylethylphosphonates and synthesis of phosphonic acid analogues of L-phenylalanine and L-tyrosine
α-Hydroxyphosphonates (±)-3, prepared by base catalysed addition of phosphites 2 to aldehydes 1, were acylated to give esters (±)-4. Diethyl 1-acyloxy-2-arylethylphosphonates (±)-4a, 4b, and 4e were hydrolysed by lipase from Aspergillus niger in a biphasic system to afford (R)-α-hydroxyphosphonates of low enantiomeric purity. The corresponding diisopropyl phosphonates (±)-4c, 4f and 4g gave (S)-α-hydroxyphosphonates
通过将亚磷酸酯2碱催化加成到醛1中而制得的α-羟基膦酸酯(±)-3被酰化,得到酯(±)-4。在双相系统中,通过来自黑曲霉的脂肪酶水解1-酰氧基-2-芳基乙基膦酸二乙酯(±)-4a,4b和4e,得到对映体纯度低的(R)-α-羟基膦酸酯。相应的二异丙基膦酸酯(±)-4c,4f和4g得到(S)-α-羟基膦酸酯,ee最高可达78%。通过其(R)-MTPA-酯的31 P NMR光谱法确定了α-羟基膦酸酯的绝对构型。化合物3a和3e分别通过其叠氮化物化学转化为L-苯丙氨酸和L-酪氨酸的膦酸类似物。
Nonenzymatic kinetic resolution of racemic β-hydroxyalkanephosphonates with a chiral copper catalyst
Kinetic resolution of beta-hydroxyalkanephosphonates was efficiently performed by 2-fluorobenzoylation in the presence of copper(II) triflate and (R,R)-Ph-BOX as a catalyst with good s value of up to 21 (C) 2010 Elsevier Ltd. All rights reserved.
Nonenzymatic kinetic resolution of racemic α-hydroxyalkanephosphonates with chiral copper catalyst
作者:Yosuke Demizu、Atsushi Moriyama、Osamu Onomura
DOI:10.1016/j.tetlet.2009.07.003
日期:2009.9
Kinetic resolution of alpha-hydroxyalkanephosphonates was efficiently performed by benzoylation in the presence of copper(II) triflate and (R,R)-Ph-BOX as a catalyst with excellent s value of up to 286. (C) 2009 Elsevier Ltd. All rights reserved.