公开了带有二和三取代烯烃的芳族和脂族烯丙基磷酸酯的有效对映选择性Cu催化的烯丙基烷基化。在 10 mol% 容易获得的手性氨基酸基配体(5 步,40% 总产率合成)和 5 mol% (CuOTf)2 x C6H6 存在下,对映选择性 CC 键形成反应得到促进。反应区域选择性地以 78-96% ee 传递叔和四元立体碳中心。提供了有关配体结构变化对烷基化过程的效率和对映选择性的影响的数据,以及机械工作模型。建议的模型涉及手性 Cu 络合物的双重作用:Cu(I) 中心与烯烃的结合是通过配体羰基之间的两点结合来促进的
Amino Acids and Peptides. VI. Novel Peptide Bond Formation catalyzed by Metal Ions. IV. Formation of optically Active Amino Acid Amides and Peptide Amides
The Cu (II)-catalyzed peptide bond formation previously reported by us, was applied to the synthesis of optically active amino acid amides and peptide amides. Treatment of an optically active amino acid ester with a primary amine in the presence of anhydrous CuCl2 afforded the desired amino acid secondary amide, without racemization, in 60-70% yield. However, the same reaction with a secondary amine with larger steric hindrance than primary amine gave an optically active tertiary amide in a very low yield as expected from the proposed mechanism. Almost all the amino acid amides could be isolated as hydrochlorides or as free bases. Some peptide amides, i. e. Z-Gly-Gly-NH-Bzl, and Z-Ala-Gly-NH-Bzl, were also prepared.
Stereoselective syntheses of 1H-imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones†
作者:Alan R. Katritzky、Yong-Jiang Xu、Hai-Ying He、Peter J. Steel
DOI:10.1039/b104060j
日期:——
1H-Imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones 6a–i are synthesized in 67–96% yields with high stereoselectivities (de 88–99%, except 6e with a 58% de value) via intermolecular condensation of 2-formylbenzoic acid (5) and α-amino amides 4a–i in the presence of a catalytic amount of toluene-p-sulfonic acid. Intermediates 4 are obtained in two steps from easily available chiral N-Boc-α-amino acids 1.
of Plasmodium, especially P. falciparum (Pf). In this view, the development of new antiplasmodial agents that are able to act via innovative mechanisms of action, is crucial to ensure efficacious antimalarial treatments. In one of our previous communications, we described a novel class of compounds endowed with high antiplasmodial activity, characterized by a pharmacophore never described before as
A new antimalarial pharmacophore has been obtained starting from previously described dual inhibitors of Plasmodium falciparum.
从先前描述的疟原虫的双重抑制剂出发,得到了一种新的抗疟药物药效团。
Tandem Isomerization/α,β-Site-Selective and Enantioselective Addition Reactions of <i>N</i>-(3-Butynoyl)-3,5-dimethylpyrazole Induced by Chiral π–Cu(II) Catalysts
of N-(3-butynoyl)-3,5-dimethyl-1H-pyrazole to generate N-allenoylpyrazole in situ and subsequent α,β-site-selective and enantioselective [3 + 2], [4 + 2], or [2 + 2] cycloaddition or conjugateaddition reactions. The asymmetric environment created by the intramolecular π–Cu(II) interactions provides the corresponding adducts in moderate to high yield with excellent enantioselectivity. To the best of