Reaction of N-benzoyl amino acids with oxalyl chloride: a facile route to 4-substituted 2-phenyloxazole-5-carboxylates
作者:Tadeusz Cynkowski、Grazyna Cynkowska、Paul Ashton、Peter A. Crooks
DOI:10.1039/c39950002335
日期:——
N-benzoyl amino acids 1a–g react with excess oxalyl chloride at room temperature followed by addition of alcohols to afford 4-substituted 2-phenyloxazole-5-carboxylates 3a–g.
which the cooperativity of two Pd centers has already been demonstrated. To get more insight into the role of the Pd/Pd distance in such metallocene bismetallacycles, in the present study a corresponding ruthenocene based Pd2-complex has been prepared by the first direct diastereoselective biscyclopalladation of a chiral ruthenocene ligand. In addition, the first highly diastereoselective direct monocyclopalladation
Metallaphotoredox‐Catalyzed Enantioselective Cross‐Electrophile Coupling Using Alcohols as Reducing Agents
作者:Zhilong Li、Leitao Huan、Jian Li、Xiaomin Shu、De Zhong、Wenjing Zhang、Haohua Huo
DOI:10.1002/anie.202305889
日期:2023.8
An enantioselective coupling of α-amino acid derivatives and aryl bromides, using Ni/photoredox catalysis and alcohols as reducingagents, is reported. This protocol offers modular access to enantioenriched benzylic amines from abundant precursors, and is suitable for late-stage diversification with broad functional group tolerance. The alcohol-based approach holds potential as a general platform for
Asymmetric Synthesis of Functionalizable Type II β-Turn-Inducing α-Amino Acid Building Blocks
作者:Wenzheng Gao、Jiaxin Han、Sophie Greaves、Joseph P. A. Harrity
DOI:10.1021/acs.orglett.3c02376
日期:2023.9.8
α-amino acids, and in so doing, the side chain is sacrificed during the ring-forming process. We report a new asymmetric approach to lactam-constrained α-amino acid building blocks bearing a range of polar and hydrophobic side chains. The chemistry is amenable to rapidly generating di- and tripeptides, and the potential for these lactams to stabilize type II β-turns is demonstrated in the synthesis of the
肽模拟物正在成为一类有前途的有效和选择性疗法。在目前这些化合物的方法中,限制性内酰胺的利用是增强活性肽构象的关键因素,开发有效和立体控制的方法来生成此类内酰胺结构单元是一个重要目标。目前的方法通常依赖于现有 α-氨基酸的精制,这样做时,侧链在成环过程中被牺牲。我们报告了一种新的不对称方法,用于构建带有一系列极性和疏水侧链的内酰胺限制的 α-氨基酸结构单元。该化学物质适合快速生成二肽和三肽,并且这些内酰胺稳定 II 型 β 转角的潜力在黑素细胞抑制因子拟肽的合成中得到了证明。
Direct introduction of glycine/mercaptoacetic acid units into electron-poor alkenes: a novel route to functionally rich α-amino/α-mercapto acids
作者:Lal Dhar S. Yadav、Ankita Rai
DOI:10.1016/j.tetlet.2008.07.103
日期:2008.9
The first example of an operationally simple direct introduction of glycine/mercaptoacetic acid units into electron-poor alkenes is reported. In this protocol, Lewis acid-catalyzed Michael addition of activated glycine or mercaptoacetic acid, that is 2-phenyl-1,3-oxazol-5-one or 2-methyl-2-phenyl-1,3-oxathiolan-5-one, to various electron-poor alkenes in water/1,4-dioxane (1:2, v/v) solvent system diastereoselectively affords the corresponding functionally rich alpha-amino acids or alpha-mercapto acids, respectively, in high yields at ambient temperature. (C) 2008 Elsevier Ltd. All rights reserved.