报道了一种有效的铑催化合成环戊烯酮的方案,该方案基于丙烯酸、甲醛和丙二酸酯通过乙烯基 C-H 活化的三组分反应。探索性研究表明,通过用 Na 2 CO 3 /MeOH 溶液处理各种烷基卤化物,可以顺利地实现所制备的环戊烯酮的 5-烷基化。过量的甲醛和丙二酸酯导致多组分反应,通过迈克尔加成得到多取代的环戊烯酮。
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
作者:Bram B. C. Peters、Jira Jongcharoenkamol、Suppachai Krajangsri、Pher G. Andersson
DOI:10.1021/acs.orglett.0c04012
日期:2021.1.1
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir–N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated
Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact
作者:Youngchan Kim、Sukbok Chang
DOI:10.1002/anie.201508669
日期:2016.1.4
valuable α‐silyl carbonyl products. The α‐silylation occurs chemoselectively, thus leaving the labile carbonylgroups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α‐silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4‐hydrosilylation of conjugated carbonyls and then slow
本文描述了由B(C 6 F 5)3催化的α,β-不饱和酯和酰胺的氢化硅烷化反应,以提供具有合成价值的α-甲硅烷基羰基产物。α-甲硅烷基化是化学选择性发生的,因此保留了不稳定的羰基。该反应具有无环和环状底物的广泛范围,并且还证明了所得α-甲硅烷基羰基产物的合成效用。机理研究揭示了两个操作步骤:共轭羰基的快速1,4-氢化硅烷化,然后减慢甲硅烷基醚中间体的甲硅烷基迁移。
Synthesis and Antiplasmodial Activity of Bicyclic Dioxanes as Simplified Dihydroplakortin Analogues
Here we report the synthesis and evaluation of antiplasmodial activity of a novel series of bicyclic peroxides inspired by the marine natural compound dihydroplakortin. We developed a synthetic strategy leading to the dihydroplakortin-related peroxides in only a few steps. The in vitro antiplasmodial potency of the peroxides was similar to, or greater than, that of the reference natural compound, and
Synthesis of 2-Hydroxy-3-oxocarboxylic Esters From the Corresponding α,β-Unsaturated Esters by a Simple One-Step Procedure
作者:D. H. G. Crout、D. L. Rathbone
DOI:10.1055/s-1989-27142
日期:——
A convenient one-step synthesis of 2-alkyl-2-hydroxy-3-oxocarboxylic esters by potassium permanganate oxidation of the corresponding readily available α,β-unsaturated esters is described. Preparation of the latter by the phosphonate modification of the Wittig reaction is also reported.