Stereoselective Synthesis of (E)-α,β-Dehydroamino Acid Esters
Stereoselective Synthesis of (E)-α,β-Dehydroamino Acid Esters
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(E)-α,β-脱氢氨基酸酯的立体选择性合成
DOI：
10.1002/ejoc.201300112
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Y. Ohfune
中科院分区：
文献类型：
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作者：
Y. Yasuno;M. Hamada;T. Yamada;T. Shinada;Y. Ohfune
脱氢氨基酸（Dhaa）是研究氨基酸和多肽的重要底物。虽然立体选择性合成的药物更稳定的Z-Dhaa已经很好地检查和建立，立体选择性合成的E-Dhaa仍然是一个具有挑战性的合成任务。本文报道了用一种新的（α-二苯基膦酰基）甘氨酸立体选择性地合成E-Dhaa酯的方法。新方法的特征方面总结如下：（i）金属添加剂在促进E-立体选择性中起重要作用。(ii)NaI的使用实现了带有芳基取代基和氨基官能团的E-Dhaas的合成，（iii）MgBr 2·OEt 2和ZnCl 2有助于改善带有烷基取代基和氧官能团的E-Dhaas的E-立体选择性合成，（iv）各种保护基和官能团在反应条件下是相容的，和（v）N-Cbz，Boc，和酰基-α-（二苯基膦酰基）甘氨酸进行立体选择性烯化反应，得到相应的E-Dhaas。
Dehydroamino acid (Dhaa) is recognized as a useful tool or substrate for amino acid and peptide research. Although the stereoselective synthesis of the thermodynamically more stableZ‐Dhaa has been well examined and established, the stereoselective synthesis ofE‐Dhaa has still remained to be a challenging synthetic task. In this paper, a stereoselective synthesis ofE‐Dhaa esters using a new (α‐diphenylphosphono)glycine is described. The characteristic aspects of the new method are summarized as follows: (i) metal additives play an important role in the promotion ofE‐stereoselectivities. (ii) the use of NaI was effected for the synthesis ofE‐Dhaas bearing an aryl substituent and an amino functionality, (iii) MgBr2·OEt2and ZnCl2contributed to improve theE‐stereoselective synthesis ofE‐Dhaas bearing an alkyl substituent and an oxygen functionality, (iv) various protecting and functional groups were compatible under the reaction conditions, and (v)N‐Cbz, Boc, and acyl‐α‐(diphenylphosphono)glycines were served for the stereoselective olefination reaction to provide the correspondingE‐Dhaas.