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。
A Methylidene Group in the Phosphonic Acid Analogue of Phenylalanine Reverses the Enantiopreference of Binding to Phenylalanine Ammonia-Lyases
formed prosthetic 3,5-dihydro-4-methylidene-5H-imidazol-5-one (MIO) group. MIO enzymes catalyze the stereoselective synthesis of α- or β-amino acid enantiomers, making these chemical processes environmentally friendly and affordable. Characterization of novel inhibitors enables structural understanding of enzyme mechanism and recognizes promising herbicide candidates as well. The present study found that