Ring-Closure Reactions of 1,2-Diaza-4,5-benzoheptatrienyl Metal Compounds: Experiment and Theory
作者:Tillmann Kleine、Klaus Bergander、Roland Fröhlich、Birgit Wibbeling、Ernst-Ulrich Würthwein
DOI:10.1021/jo2001534
日期:2011.4.1
5-benzoheptatrienyl metal compounds 1a−m by treatment with KO-t-Bu as base. These metal compounds undergo the various types of reactions in good yields and exclusively depending on the nature of substituents R1 and R3. Thus, metal compounds 1a−c carrying alkyl substituents R1 and R3 form 3H-benzodiazepines 6a−c after electrophilic quench of the intermediate cyclic anion 7 in a 7-endo-trig electrocyclic reaction with
2- Alkenylbenzylidene腙5A -米,这是在良好的在一个四步合成优异的产率可访问的,被转换成1,2-二氮杂-4,5- benzoheptatrienyl金属化合物1A -米通过用KO-吨-Bu作为基础。这些金属化合物以良好的产率并且仅取决于取代基R 1和R 3的性质进行各种类型的反应。因此,带有烷基取代基R 1和R 3的金属化合物1a - c形成3 H-苯并二氮杂6a - c后的中间环状阴离子的亲电淬火7在7-内-TRIG与莫比乌斯芳香过渡结构电环化反应1 - -TS。类似地,苯并噻吩基衍生物5n被转化为二氮杂66d。在R 3上被N-甲基和芳基取代的钾化合物1d-h在主要由电荷控制的6 -exo-trig环化反应中形成1,2-二氢酞嗪8a - e。相反,芳基-芳基取代的系统5i - m脱质子化反应不会产生环状产物,但是中间体开链金属化合物1i - m在N1处被酰氯捕获,生成酰肼10a-e