SpinPhox/Iridium(I)-Catalyzed Asymmetric Hydrogenation of Cyclic α-Alkylidene Carbonyl Compounds
作者:Xu Liu、Zhaobin Han、Zheng Wang、Kuiling Ding
DOI:10.1002/anie.201309521
日期:2014.2.10
cyclic carbonyl compounds bearing an α‐chiral carbon center are of interest in pharmaceutical sciences and asymmetric synthesis. Herein, SpinPhox/IrI catalysts have been demonstrated to be highly enantioselective in the asymmetric hydrogenation of the CC bonds in the exocyclicα,β‐unsaturated cyclic carbonyls, including a broad range of α‐alkylidene lactams, unsaturated cyclic ketones, and lactones. It
带有α-手性碳中心的旋光中型环状羰基化合物在制药科学和不对称合成中引起人们的兴趣。在本文中,SpinPhox / Ir I催化剂在环外α,β-不饱和环状羰基化合物(包括各种α-亚烷基内酰胺,不饱和环状酮)中的CC键的不对称氢化中被证明具有高度对映选择性。内酯。值得注意的是,该方法可以成功地用于具有六元或七元环的具有挑战性的α-烷基亚内酰胺底物的不对称氢化,从而提供相应的具有α-手性碳中心的旋光羰基化合物,其对映体过量通常非常好(高达ee的98% )。该协议的合成用途还已在抗炎药洛索洛芬及其类似物以及生物学上重要的ε-氨基己酸衍生物的不对称合成中得到证明。
Natural α-methylenelactam analogues: Design, synthesis and evaluation of α-alkenyl-γ and δ-lactams as potential antifungal agents against Colletotrichum orbiculare
In our continued efforts to improve the potential utility of the alpha-methylene-gamma-lactone scaffold, 62 new and 59 known natural alpha-methylenelactam analogues including alpha-methylene-gamma- lactams, alpha-arylidene- gamma and delta-lactams, and 3-arylideneindolin-2-ones were synthesized as the bioisosteric analogues of the amethylenelactone scaffold. The results of antifungal and cytotoxic activity indicated that among these derivatives compound (E)-1-(2, 6-dichlorobenzyl)-3-(2-fluorobenzylidene) pyrrolidin-2-one (Py51) possessed good selectivity with the highest antifungal activity against Colletotrichum orbiculare with IC50 - 10.4 mu M but less cytotoxic activity with IC50 - 141.2 mu M (against HepG2 cell line) and 161.2 mu M ( against human hepatic L02 cell line). Ultrastructural change studies performed by transmission electron microscope showed that Py51 could cause important cell morphological changes in C. orbiculare, such as plasma membrane detached from cell wall, cell wall thickening, mitochondria disruption, a dramatic increase in vacuolation, and eventually a complete loss in the integrity of organelles. Significantly, mitochondria appeared one of the primary targets, as confirmed by their remarkably aberrant morphological changes. Analysis of structureeactivity relationships revealed that incorporation of the aryl group into the alpha-exo methylene and the N-benzyl substitution increased the activity. Meanwhile, the alpha-arylidene-gamma-lactams have superiority in selectivity over the 3-arylideneindolin-2-ones. Based on the results, the N- benzyl substituted a-(2-fluorophenyl)-gamma-lactam was identified as the most promising natural- based scaffold for further discovering and developing improved crop- protection agents. (c) 2017 Elsevier Masson SAS. All rights reserved.
Olefination of 3-diazopiperidin-2-one
作者:Richard Harrison、Antonio Mete、Lauren Wilson
DOI:10.1016/s0040-4039(03)01680-0
日期:2003.8
New conditions have been developed for the olefination of diazo compounds catalysed by methyl trioxorhenium. The new system is suitable for unreactive diazo compounds and its utility is demonstrated by the olefination of 3-diazopiperidin-2-one with a range of aromatic, heterocyclic and alkylaldehydes. (C) 2003 Elsevier Ltd. All rights reserved.