Enzymes in Organic Chemistry, Part 2: Lipase-catalysed Hydrolysis of 1-Acyloxy-2-arylethylphosphonates and Synthesis of Phosphonic Acid Analogues of L-Tyrosine

Article abstract of DOI:10.1016/0040-4020(95)98691-A

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 lypase 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 with an ee of up to 78percent.The absolute configuration of the α-hydroxyphosphonates was assigned by 31P NMR spectroscopy of their (R)-MTPA-esters. (S)-3b and 3e were chemically transformed via their azides to phosphonic acid analogues of L-phenylalanine and L-tyrosine, respectively.