Asymmetric syntheses of β-phenylalanine, α-methyl-β-phenylalanines and derivatives
作者:Stephen G. Davies、Narciso M. Garrido、Osamu Ichihara、Lain A. S. Walters
DOI:10.1039/c39930001153
日期:——
A strategy of highly stereoselective conjugate additions of lithium (R)-(α-methylbenzyl)benzylamide to tert-butyl cinnamate and its 2-methyl derivative combined with appropriate tandem or sequential electrophilic quenches allows the asymmetric syntheses of β-phenylalanine (95% enantiomeric excess) and homochiral (2R, 3S)- and (2S, 3S)-α-methyl-β-phenylalanine and the corresponding β-lactams (3R, 4S)- and (3S, 4S)-3-methyl-4-phenylazetidinones.
锂 (R)-(α-甲基苄基) 苄基酰胺的高度立体选择性共轭加成到肉桂酸叔丁酯及其 2-甲基衍生物的策略与适当的串联或顺序亲电猝灭相结合,允许不对称合成 β-苯丙氨酸 (95%对映体过量)和纯手性(2R,3S)-和(2S, 3S)-α-甲基-β-苯丙氨酸和相应的β-内酰胺(3R,4S)-和(3S,4S)-3-甲基-4-苯基氮杂环丁酮。