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DFT Study on the (S)-Proline-catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde
1 INTRODUCTION Aldol reaction, one of the most important C–C bond-formation reactions, is widely utilized in orga- nic synthesis[1]. Extensive efforts have been donated to the development of catalytic stereo-selective va- riants of this reaction[2]. However, the direct aldol reaction between unmodified carbonyles would be the most attractive synthetic alternative. Proline-catalyzed intermolecular direct aldol reac- tion between acetone and 4-nitrobenzaldehyde was first reported by List… 相似文献
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用Huckel分子轨道法(HMO)计算研究了苯和甲苯的硝基衍生物及其两电子(n=2)和四电子(n=4)的还原产物亚硝基化合物和苯基羟胺化合物。发现在各pH下苯和甲苯硝基衍生物的极谱还原电位(E_(1/2)),均与n=2反应前后分子的最低空轨道能量系数和(m_LUMO~(1)+m_LUMO~(2))以及与n=4反应前后分子的能量差之间,存在良好的线性关系。运用这些规律有助于阐明芳香族多硝基化合物的极谱还原过程。本文据此预示了一些化合物的未知E_(1/2)。 相似文献
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1 INTRODUCTION Zeolites have attracted much attention in both scientific and industrial areas for their special characteristics and multiple uses. Zeolites are composed of TO4 (T = Si, Al, Ga, P, etc.) tetrahedra which are connected with each other by sharing oxygen atoms to produce a complex and repetitive three-dimensional atom network with regular molecular dimension cavities joined by channels. Shape selectivity is the most important property of zeolites. Combined with the possib… 相似文献
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本文运用单纯形最优化法,测定了V(V)-PAR-H2O2以及W(Ⅵ)PV-CTMAB三元配合物的组成比。提出了对应于三元配合物的λmax处二元配合物也有部分吸收时的二种处理办法及体系最初酸度调节的新看法,并经上述三元配合物体系,验证了方法的可行性,进一步完善了单纯形最优化法测配合物组成比这一手段。 相似文献
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本文研究运用改良单基本原理建立了单纯形推移计算公式,结合分光光度法首次研究并报道了V(Ⅴ)-NH2OH-PAR三元配合物的组成比,三种不同初始单纯形下,均获得组成比为2+1+2。该法简便,快速,准确度较高,且可克服传统的三元相图法需绘图等缺点。 相似文献