The Adverse Effect of Benzannelation on the Aromaticity of Oxocinyl Anion: A Combined Experimental and Theoretical Study
作者:Hamid S. Kasmai、Xiaodong Wang、Hanh-Nhon Doan、Josef F. Femia、Thad M. Yablonsky、Mary E. Read、David T. Dutton
DOI:10.1002/hlca.200900430
日期:——
f]oxocinyl anions were generated from their corresponding conjugate acid precursors 7c and 8, respectively. It was found that 2H‐1‐benzoxocinide 3d lacks the type of π‐frame stability associated with the parent 2H‐oxocinide 1d and that the dibenzo analog 5b is more unstable than 3d. Both 3d and 5b undergo rapid structural reorganization to form their corresponding stable isomeric anions. We were able
从容易获得的化合物完成了2 H -1-苯并氧还蛋白的合成。潜在的“芳香族” π-过量体系2 H -1-苯并氧代辛基和6 H-二苯并[ b,f ]氧代辛基阴离子分别从其相应的共轭酸前体7c和8生成。发现2 H -1-苯并氧代烟酰胺3d缺乏与母体2 H-氧代烟酰胺1d相关的π框架稳定性,并且二苯并类似物5b比3d更不稳定。两个都3d和5b经历快速的结构重组以形成它们相应的稳定的异构体阴离子。我们能够将这些阴离子的质子猝灭产物分别表征为开环结构15和18。1 H-NMR和从头算在6-31g *的水平表明,与'芳族'母体2 H-氧代辛酯1d和aza类似物3c不同,3d引入了非平面的氧代辛基环,其中负电荷为主要位于环的戊二烯基部分,但π电子密度在电子环上的部分离域也发生在苯环上。