Rhodium-Catalyzed Oxidative 1:1, 1:2, and 1:4 Coupling Reactions of Phenylazoles with Internal Alkynes through the Regioselective Cleavages of Multiple C−H Bonds
作者:Nobuyoshi Umeda、Koji Hirano、Tetsuya Satoh、Naoto Shibata、Hirofumi Sato、Masahiro Miura
DOI:10.1021/jo1021184
日期:2011.1.7
selectively through the coupling of 1-phenylpyrazole and diphenylacetylene in 1:1, 1:2, and 1:4 manners, respectively. The reactions preferentially take place at the electron-deficient sites on the aromatic substrates. A comparison of reactivities of variously substituted and deuterated substrates sheds light on the mechanism of C−H bond cleavage steps. The reaction pathway is highly dependent on reaction
在铑催化剂和铜氧化剂伴有双或四键CH键断裂的情况下,苯唑与内部炔烃的直接氧化偶联有效地进行。因此,作为代表性的例子,4,5-二苯基吡唑并[1,5- a]喹啉,1-(1,2,3,4-四苯基萘-5-基)吡唑和1-(1,2,3,4,5,6,7,8-八苯基蒽-9-基)吡唑可以通过分别以1:1、1:2和1:4的方式通过1-苯基吡唑和二苯基乙炔的偶合来选择性获得。该反应优选在芳族底物上的电子不足的位置发生。各种取代和氘代底物的反应性比较揭示了CH键断裂步骤的机理。反应路径高度依赖于所采用的反应条件,特别是取决于溶剂的性质。关键的rhodocycle中间体的溶剂化的影响已进行了计算研究。另外,已经发现一些稠合的芳族产物在固态下表现出强烈的荧光。