Highly Stereoselective Syntheses of Optically Active beta, gamma-Unsaturated Amino Acids.

我们开发了两种合成光学活性(E) -2-（芳基乙烯基）甘氨酸衍生物的方法。(1)在本研究中，n保护的3-（三苯基膦）丙氨酸盐被证明只适用于与芳香醛的Witting反应，而异丁醛、环己酮和二苯甲酮被证明不适用于该反应。(2)以N-（甲氧羰基）-3-（三苯基膦）丙氨酸为原料，采用Wittig反应，改进了合成苯丙氨酸转移核糖核酸超修饰碱的光纯关键中间体。(3)上述Wittig反应成功应用于核苷水平的合成。首次合成了大鼠肝脏苯丙氨酸转移核糖核酸超修饰核苷最可能的替代品。(4)对于(S) - n -（苯氧羰基）乙烯基甘氨酸和4-碘苯甲醚在H_2O中进行Heck反应，从光学收率的角度来看，NaHCO_3O是测试碱中最好的。(5)本研究确定了上述Heck反应的范围和局限性。以高度立体选择性的方式，以51-66%的收率从苯基、甲苯基、茴香基和萘碘化物中获得了各种ee为95-98%的(E) -（2-芳基乙烯基）甘氨酸。然而，2-、3-和4-溴苯基碘化物提供了相对较低的光学纯度（85-90% ee）的烯烃，收率为30-51%；含吸电子的4-硝基或4-乙酰基的碘苯产率很低。杂环碘化物如噻吩、咪唑和咪唑[1,2- α] purin-9-ones取得了有限的成功。

We have developed two methods for synthesis of optically active (E) -2- (arylvinyl) glcine derivatives.(1) In the present investigation N-protected 3- (triphenylphosphonio) alaninates are shown to be useful for the Witting reaction only with aromatic aldehydes : isobutyralehyde, cyclohexanone, and benzophenone proved unsuitable for this reaction.(2) Improved synthesis of the optically pure key intermediate for the synthesis of hypermodified bases of phenylalanine transfer ribonucleic acids was achieved by the Wittig reaction employing N- (methoxycarbonyl) -3- (triphenylphosphonio) alaninate.(3) The Wittig reaction described above was successfully applied to the synthesis at the nucleoside level. Thus, the most probable alternatives for the hypermodified nucleoside of rat liver phenylalanine transfer ribonucleic acid was synthesized for the forst time.(4) For the Heck reaction between (S) -N- (benzyloxycarbonyl) vinylglycine and 4-iodoanisole in H_2O,NaHCO_3O was shown to be best of the bases tested from a viewpoint of optical yield.(5) Scope and limitations of the Heck reaction described above was established in the present study.Various (E) - (2-arylvinyl) glycines of 95-98% ee were obtained in highly stereoselective manners in 51-66% yields from phenyl, tolyl, anisyl, and naphthyl iodides. However, 2-, 3-, and 4-bromophenyl iodides provided the corresponding olefins of somewhat low optical purity (85-90% ee) in 30-51% yields ; iodobenzenes carying an electronwithdrawing 4-nitro or 4-acetyl group gave poor yields of products. Limited success was accomplished with iodides of heterocycles such as thiophene, imidazole, and imidazo [1,2-alpha] purin-9-ones.