The synthesis and structures of arene-substituted azadipyrromethenes
摘要:
We present the synthesis of several azadipyrromethenes with four peripheral arene units which can be readily generated via the well-established chalcone synthetic method. The stability and yields of these azadipyrromethenes is highly dependent on the nature of the arene substituent, with the bis-pyridine systems exhibiting the highest degree of instability. The structures of several of the compounds and their BF2 adducts are presented; intramolecular hydrogen bonding is observed in the free base ADPMs. We also present a study into the absorption and emission properties of the ADPMs and their BF2 adducts and observe that they are also highly dependent on the identity of the substituents. (C) 2015 Elsevier Ltd. All rights reserved.
Enantioselective Nickel-Catalyzed Michael Additions of 2-Acetylazaarenes to Nitroalkenes
作者:Alain J. Simpson、Hon Wai Lam
DOI:10.1021/ol400578c
日期:2013.6.7
2-Acetylazaarenes undergo catalytic enantioselective Michaeladditions to nitroalkenes in the presence of a chiral Ni(II)–bis(oxazoline) complex. The process is tolerant of a range of azines or azoles in the pronucleophilic component, resulting in Michael products in moderate to high enantioselectivities.
Enantioselective La<sup>III</sup>-pyBOX-Catalyzed Nitro-Michael Addition to (<i>E</i>)-2-Azachalcones
作者:Gonzalo Blay、Celia Incerti、M. Carmen Muñoz、José R. Pedro
DOI:10.1002/ejoc.201201579
日期:2013.3
[La(OTf)3] complex with a new pyBOX ligand bearing a bulky 1-naphthylmethyl substituent at the 4′-position of the oxazoline ring catalyzes the conjugate addition of nitroalkanes to a broad range of (E)-2-azachalcones, providing the expected nitro-Michael products with good yields and enantiomeric excesses up to 87 %. The optical purity of the products can be increased by a single crystallization. A plausible
Chiral Covalent Organic Cages: Structural Isomerism and Enantioselective Catalysis
作者:Kaixuan Wang、Xianhui Tang、Bai Amutha Anjali、Jinqiao Dong、Jianwen Jiang、Yan Liu、Yong Cui
DOI:10.1021/jacs.3c12555
日期:2024.3.13
orientations of four tetraaldehyde units with respect to each other. One isomer (PN-1) has an unprecedented Johnson-type J26 structure, whereas another (PN-2) adopts a tetragonal prismatic structure. After the reduction of the imine linkages, the cages are transformed into two amine bond-linked isomers PN-1R and PN-2R. After binding to Ni(II) ions, both can serve as efficient catalysts for asymmetric Michael
Enantiomerically pure carbamate-monoprotected trans-cyclohexane-1,2-diamines are used as chiral organocatalysts for the addition of aryl ketones and acetone to nitroalkenes to give enantioenriched beta-substituted gamma-nitroketones. The reaction was performed in the presence of 3,4-dimethoxybenzoic acid as an additive, in chloroform as the solvent at room temperature, achieving enantioselectivities up to 96%. Theoretical calculations are used to justify the observed sense of the stereoinduction. (C) 2015 Elsevier Ltd. All rights reserved.
Solvent-free enantioselective conjugate addition and bioactivities of nitromethane to Chalcone containing pyridine
作者:Guoping Zhang、Chun Zhu、Dengyue Liu、Jianke Pan、Jian Zhang、Deyu Hu、Baoan Song
DOI:10.1016/j.tet.2016.11.063
日期:2017.1
catalysts in the enantioselective Michael additions of nitromethane to α,β-unsaturated ketones containing pyridine. The best results were obtained with the bifunctional catalyst prepared from 3,5-di(trifluoromethyl)-aniline under solvent-free conditions. This thiourea promoted the reaction with high enantioselectivities and chemical yields for aryl ketones. The origins of enantioselectivity were further