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 stable Z-Dhaa has been well examined and established, the stereoselective synthesis of E-Dhaa has still remained to be a challenging synthetic task. In this paper, a stereoselective synthesis of E-Dhaa esters using a new (α-d
脱氢氨基酸 (Dhaa) 被认为是氨基酸和肽研究的有用工具或底物。尽管热力学上更稳定的 Z-Dhaa 的立体选择性合成已得到充分研究和确立,但 E-Dhaa 的立体选择性合成仍然是一项具有挑战性的合成任务。在本文中,描述了使用新的(α-二苯基膦酰基)甘氨酸立体选择性合成 E-Dhaa 酯。新方法的特征方面总结如下:(i)金属添加剂在促进 E 立体选择性方面起着重要作用。(ii) NaI 用于合成带有芳基取代基和氨基官能团的 E-Dhaas,
Regioselective Synthesis of Substituted Pyrroles: Efficient Palladium-Catalyzed Cyclization of Internal Alkynes and 2-Amino-3-iodoacrylate Derivatives
作者:Matthew L. Crawley、Igor Goljer、Douglas J. Jenkins、John F. Mehlmann、Lisa Nogle、Rebecca Dooley、Paige E. Mahaney
DOI:10.1021/ol062424p
日期:2006.12.1
The first efficient and regioselective palladium-catalyzedcyclization of internal alkynes and 2-amino-3-iodoacrylates to give moderate to excellent yields of highly functionalized pyrroles has been developed. This approach is applicable to a range of alkynes and affords the deacylated pyrrole under reaction conditions for most substrates. [reaction: see text]
total synthesis of (−)-kaitocephalin, a novel antagonist of ionotropic glutamate receptors, was accomplished in 12 steps starting from 5-substituted proline ester via the aldol reaction with OBO-serine aldehyde, (E)-selective α,β-dehydroaminoacid synthesis using a new HWE reagent, and catalytic hydrogenation.
The rearrangement of (E)-didehydroamino acid derivatives to the corresponding Z-derivatives under acid or basic catalysis as well as under the influence of radicals has been investigated. The condensation of N-benzyloxycarbonyl or N-tert-butoxycarbonyl protected alkyl 2-amino-2-(dimethoxyphosphoryl)acetates with aldehydes or ketones in dichloromethane in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene furnishes (Z)-didehydroamino acid ester derivatives diastereoselectively in excellent yields and with high purity.
研究了在酸或碱催化以及自由基影响下,(E)-二脱氢氨基酸衍生物重排为相应的 Z 衍生物的过程。在 1,8- 二氮杂双环[5.4.0]十一碳-7-烯存在下,N-苄氧羰基或 N-叔丁氧羰基保护的 2-氨基-2-(二甲氧基磷酰)乙酸烷基酯与醛或酮在二氯甲烷中缩合,可产生非对映选择性的 (Z)-二脱氢氨基酸酯衍生物,收率极高,纯度也很高。
A Stereospecific Elimination to Form Dehydroamino Acids: Synthesis of the Phomopsin Tripeptide Side Chain
作者:Michelle M. Stohlmeyer、Hiroko Tanaka、Thomas J. Wandless
DOI:10.1021/ja991037q
日期:1999.6.1
An increasing interest in R,â-dehydroamino acids has developed in recent years based both on their importance as commodity chemicals and their presence in biologically activenatural products. Efficient methods for the asymmetric hydrogenation of R,â-dehydroamino acids allow access to a wide variety of unnatural amino acids.1 Dehydroamino acids are also found in many natural products including the antrimycins