Discreteness of π-conjugation of 1,6-methano[10]annulene by troponoid fusion at the 3,4-positions
作者:Yanmei Zhang、Eri Hisano、Reina Ohta、Ryuta Miyatake、Yoshikazu Horino、Mitsunori Oda、Shigeyasu Kuroda
DOI:10.1016/j.tetlet.2007.11.161
日期:2008.1
The tropone-fused 1,6-methano[10]annulene 4 was synthesized from 3,4-bis(bromomethyl)-1,6-methano[10]annulene and the protonation of 4 provided the hydroxytropylium ion-fused annulene 5. 1H NMR spectra of 4 and 5 exhibited an unequal shielding effect on the bridge hydrogens from the resulted π ring system, suggesting the existence of the significant homoconjugative transannular interaction on the nonadjacent
环庚三烯酮稠合1,6-亚甲基[10]轮烯4是由3,4-双(溴甲基)-1,6-亚甲基[10]轮烯和质子化合成4提供的hydroxytropylium离子稠合的轮烯5。4和5的1 H NMR谱图显示所得π环系统对桥氢的屏蔽作用不同,这表明桥上不相邻碳原子上存在显着的均共轭跨环相互作用,且环芳烃的π共轭不连续。在C7–C8和C11–C12的两个键之间定位C8–11二烯基和其余部分。4和5的X射线晶体学结构 在这些化合物中,碳原子之间的原子距离相对较短,并且二烯基部分之间的键清澈交替,其余部分中的键收敛,从而支持光谱性质。