Dipeptide Derivatives with a Phosphonate Instead of Carboxylate Terminus byC-Alkylation of Protected (Decarboxy-dipeptidyl)phosphonates
作者:Christian Gerber、Dieter Seebach
DOI:10.1002/hlca.19910740702
日期:1991.10.30
Z-Protected diphenyl (decarboxy-dipeptidyl)phosphonates 5a-c with a (decarboxysarcosinyl)phosphonate moiety are prepared from Z-L-alanine (1a). Z-L-valine (1b), and Z-L-phenylalanine (1c) by the following series of steps: coupling with methyl sarcosinate (2a–c), saponification (3a–c), Hofer-Moest oxidative decarboxyiation by electrolysis in MeOH (4a–c), and Arbuzov reaction with P(OPh)3/TiCl4 (Scheme
由ZL-丙氨酸(1a)制备具有Z-保护的具有(脱羧肌氨酸基)膦酸酯部分的二苯基(脱羧-二肽基)膦酸酯5a - c。ZL-缬氨酸(1B),和ZL -苯丙氨酸(1C)由以下一系列步骤:用甲基肌氨酸盐偶合(图2a - C ^),皂化(图3a - Ç),Hofer的-MOEST氧化decarboxyiation通过电解在MeOH(4A - c),与Arbuzov反应与P(OPh)3 / TiCl 4(方案3)。双去质子化和烷基化导致侧链旁边的膦酸酯基团的非立体选择性的掺入(类型的产品6 - 8,9个的实例,参见方案4)。在6a – c和8c的情况下,可以分离非对映异构体,并推论新形成的立体异构中心的构型。我们将L,D-构型分配给31 P-NMR信号出现在较高场的非对映异构体。