Structure/Reactivity Relationships in the Benzo[<i>c</i>]phenanthrene Skeleton: Stable Ion and Electrophilic Substitution (Nitration, Bromination) Study of Substituted Analogues, Novel Carbocations and Substituted Derivatives
作者:Cédric Brulé、Kenneth K. Laali、Takao Okazaki、Mahesh K. Lakshman
DOI:10.1021/jo0625453
日期:2007.4.1
−OH substituents, and its stronger influence relative to methyl groups, was also observed in the nitration and bromination reactions. Charge distribution modes in the regioisomeric protonated carbocations formed via parent B[c]Ph as well as in the benzylic carbocation formed via fjord-region epoxide ring opening were deduced by gauge-invariant atomic orbital density functional theory (GIAO-DFT) and
由取代的苯并[低温质子化产生了一系列新的碳正离子的Ç ]菲,B [ Ç ] PHS和它们的电荷离域的途径是通过NMRΔδ的幅度的基础上阐明13 C值。已经显示,质子区域选择性受到甲氧基和羟基取代基的强烈控制,其指导作用优于甲基取代作用。在硝化和溴化反应中也观察到了通过-OMe和-OH取代基进行区域控制,以及其相对于甲基的更强影响。通过母体B [ c形成的区域异构质子化碳正离子中的电荷分布模式通过规变不变原子轨道密度泛函理论(GIAO-DFT)以及自然种群分析(NPA)推导了CHs上电荷的变化,推论了通过峡湾区环氧化物开环形成的] Ph以及苄基碳正离子。将这些模式与由NMR实验得出的取代衍生物进行了比较。基于核磁共振的电荷离域图谱提供了对甲基化和氟化B [ c的结构/活性关系的深入了解] Phs。在代表性案例中,在硝化和溴化反应中观察到的区域选择性与通过质子化的区域选择性相同。在本研究中合成