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

本文发展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)在本调查中，N-保护的3-（三苯基膦酰基）丙氨酸被证明是有用的Witting反应，只有与芳香醛：异丁醛，环己酮，和二苯甲酮证明不适合这个反应。(2)采用N-（甲氧羰基）-3-（三苯基膦酰基）丙氨酸通过Wittig反应改进了用于合成苯丙氨酸转移核糖核酸的高度修饰碱基的光学纯关键中间体的合成。(3)上述Wittig反应成功地应用于核苷水平的合成。首次合成了大鼠肝苯丙氨酸转移核糖核酸高修饰核苷的最有可能的替代物。(4)对于（S）-N-苄氧羰基乙烯基甘氨酸与4-碘苯甲醚在水溶液中的Heck反应，从光学产率的角度看，NaHCO_3O是最佳的碱。(5)本研究确定了上述Heck反应的范围和局限性，以高立体选择性的方式从苯基、甲苯基、茴香基和萘基碘得到了95- 98%ee的各种（E）-（2-芳基乙烯基）甘氨酸，产率为51-66%。然而，2-、3-和4-溴苯基碘以30-51%的产率提供了光学纯度稍低（85- 90%ee）的相应烯烃;带有吸电子的4-硝基或4-乙酰基的碘苯给出了差的产物产率。用杂环如噻吩、咪唑和咪唑并[1，2-α]嘌呤-9-酮的碘化物取得了有限的成功。

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.