Aryl Nitrene Rearrangements: Spectroscopic Observation of a Benzazirine and Its Ring Expansion to a Ketenimine by Heavy-Atom Tunneling
作者:Hiroshi Inui、Kazuhiro Sawada、Shigero Oishi、Kiminori Ushida、Robert J. McMahon
DOI:10.1021/ja404172s
日期:2013.7.17
cryogenic temperatures, benzazirine intermediates were identified on the basis of IR spectra. As expected, the benzazirines photochemically rearranged to the corresponding ketenimines and triplet nitrenes. Interestingly, with the methylthio substituent, the rearrangement of benzazirine 8 to ketenimine 7 occurred at 1.49 × 10(-5) s(-1) even in the dark at 10 K, despite a computed activation barrier
在低温下氩气基质中 4-甲氧基苯基叠氮化物 (1) 和 4-甲基噻吩叠氮化物 (5) 的光分解中,苯并齐林中间体在红外光谱的基础上被鉴定。正如预期的那样,苯并齐林通过光化学方式重排为相应的烯酮亚胺和三线态氮烯。有趣的是,使用甲硫基取代基,即使在 10 K 的黑暗中,benzazirine 8 重排为烯酮亚胺 7 的重排发生率为 1.49 × 10(-5) s(-1),尽管计算的激活势垒为 3.4 kcal mol(-1) . 因为这个速率比通过屏障计算的速率高 10(57) 倍,并且因为它不显示温度依赖性,所以重排机制被解释为重原子隧穿。