Expansion of Azulenes as Nonbenzenoid Aromatic Compounds for C–H Activation: Rhodium- and Iridium-Catalyzed Oxidative Cyclization of Azulene Carboxylic Acids with Alkynes for the Synthesis of Azulenolactones and Benzoazulenes
作者:Chanyoung Maeng、Jeong-Yu Son、Seung Cheol Lee、Yonghyeon Baek、Kyusik Um、Sang Hoon Han、Gi Hoon Ko、Gi Uk Han、Kyungsup Lee、Kooyeon Lee、Phil Ho Lee
DOI:10.1021/acs.joc.9b03448
日期:2020.3.6
reactivity order for C-H activation reaction is greater toward azulene-6-carboxylic acid, azulene-1-carboxylic acid, and azulene-2-carboxylic acid. For the first time, the expansion of azulenes having directing group as nonbenzenoid aromatic compounds for C-H activation was successful, indicating that nonbenzenoid aromatic compounds can be used as good substrates for the C-H activation reaction. Therefore,
在好氧条件下,通过氮杂羧酸的CH活化(作为带有对称和不对称炔烃的非苯环芳族化合物),通过铑活化a基羧酸进行的铑催化的氧化[4 + 2]环化反应,可制得具有广泛底物范围和出色的官能团耐受性的a烯内酯衍生物。有趣的是,与炔烃反应的天青烯酸经过铱催化的[2 + 2 + 2]环化并伴随脱羧作用,得到四(芳基)取代的苯并氮杂烯衍生物。CH活化反应的反应性顺序对氮杂6-羧酸,氮杂-1-羧酸和氮杂-2-羧酸更大。首次成功地将具有作为非苯甲酸酯类芳香族化合物的指导基团的天青石进行CH活化,表明非苯甲酸酯类芳香族化合物可以用作CH活化反应的良好底物。因此,未来CH活化的研究领域必将扩展到非苯甲酸酯类芳香族化合物。