Synthesis and Characterization of Unsymmetric 4-Picolyl Selenides
作者:Gurjeet Gujral、Shivani D. Gulati、Kuldip K. Bhasin、V. A. Potapov、S. V. Amosova
DOI:10.1080/10426507.2015.1085041
日期:2016.1.2
GRAPHICAL ABSTRACT Abstract A number of unsymmetrical heteroaryl 4-picolyl selenides have been prepared by lithiation of 4-picoline using lithium diisopropylamide under cryogenic conditions. The intermediate 4-lithiopicoline formed was then reacted with elemental selenium followed by the addition of suitable electrophiles to give 4-picolyl alkyl selenides. 4-Lithiopicoline was also made to react directly
Orbital Interactions in Selenomethyl-Substituted Pyridinium Ions and Carbenium Ions with Higher Electron Demand
作者:S. Fern Lim、Benjamin L. Harris、Paul Blanc、Jonathan M. White
DOI:10.1021/jo102307v
日期:2011.3.18
interaction (nSe−σ*CC) involving the selenium p-type lone pair electrons and the polarized CH2−C(Ar) σ-bond. NBO analysis of calculated cations with varying electron demand (B3LYP/6-311++G**) show that C−Se hyperconjugation (σC−Se−π*) is the predominant mode of stabilization in the weakly electron-demanding pyridinium ions (10d, 11d, 14, and 15); however, the through-space (nSe−π*) interaction becomes more
计算,溶液相和2-和4-有机硒基甲基取代的吡啶鎓离子(10a - c和11a - c)的晶体结构分析为C-Se之间的C-Se超共轭(σC -Se- π*)提供了有力证据Seσ键和π缺陷芳香环以及硒p型孤对与π缺陷芳香环之间的贯穿空间相互作用(n Se -π*)。还存在涉及硒p型孤对电子和极化CH 2的弱端基异构型相互作用(n Se- σ* CC)-C(Ar)σ键。NBO分析计算出的具有不同电子需求的阳离子(B3LYP / 6-311 ++ G **)表明,C-Se超共轭(σC -Se- π*)是弱电子需求的吡啶鎓离子的主要稳定模式。 (10d,11d,14和15);然而,随着β-Se取代的碳正离子的电子需求增加,贯穿空间(n Se -π *)相互作用变得更加重要。在所有离子中,异头相互作用(n Se- σ* CC)相对较弱。