NMR and DFT studies on persistent carbocations derived from benzo[<i>kl</i>
]xanthene, dibenzo[<i>d</i>
,<i>d</i>
′]benzo[1,2-<i>b</i>
:4,3-<i>b</i>
′]difuran, and dibenzo[<i>d</i>
,<i>d</i>
′]benzo[1,2-<i>b</i>
:4,5-<i>b</i>
′]difuran in superacidic media
作者:Takao Okazaki、Madoka Nakagawa、Takeshi Futemma、Toshikazu Kitagawa
DOI:10.1002/poc.3505
日期:2016.2
carbocations generated by the protonation of hetero‐polycyclic aromatic compounds with oxygen atom(s) were studied by experimental NMR and density function theory calculations. Benzo[kl]xanthene (1), dibenzo[d,d′]benzo[1,2‐b:4,3‐b′]difuran (2), and dibenzo[d,d′]benzo[1,2‐b:4,5‐b′]difuran (3) were synthesized by the annulation of arenediazonium salts. Compound 1 in FSO3H‐SbF5 (4:1)/SO2ClF and 3 in FSO3H‐SbF5 (1:1)/SO2ClF
通过实验NMR和密度函数理论计算研究了杂多环芳族化合物与氧原子质子化产生的持久碳阳离子。苯并[ kl ]吨蒽(1),二苯并[ d,d ']苯并[1,2- b:4,3- b ']二呋喃(2)和二苯并[ d,d ']苯并[1,2- b:4,5- b ']二呋喃(3)是通过芳构氮鎓盐的环化反应合成的。FSO 3 H-SbF 5(4:1)/ SO 2 ClF和3中的化合物1在FSO 3 H-的SbF 5(1:1)/ SO 2的ClF电离以1AH +与质子化在C(4)和四氢-3aH- +与质子化在C(6),以及这些阳离子被成功通过NMR在低温下观察到。密度泛函理论计算表明,1aH +和3aH +是最稳定的质子化碳正离子,2应当在C(6)质子化下电离为2aH +。根据在变化13个c。化学位移(Δδ 13 C)中,正电荷被离域到用于萘单元1AH+,为一个苯并[ b, d ]呋喃单元2AH +,并进入一个苯并[