Experimental and Computational Studies on the Ruthenium-Catalyzed Dehydrative C–H Coupling of Phenols with Aldehydes for the Synthesis of 2-Alkylphenol, Benzofuran, and Xanthene Derivatives
作者:Nuwan Pannilawithana、Bimal Pudasaini、Mu-Hyun Baik、Chae S. Yi
DOI:10.1021/jacs.1c06887
日期:2021.8.25
with benzaldehyde and 2-propanol/2-propanol-d8 (kH/kD = 2.3 ± 0.3). The carbon isotope effect was observed on the benzylic carbon of the alkylation product from the coupling reaction of 3-methoxyphenol with 4-methoxybenzaldehyde (C(3) 1.021(3)) and on both benzylic and ortho-arene carbons from the coupling reaction with 4-trifluorobenzaldehdye (C(2) 1.017(3), C(3) 1.011(2)). The Hammett plot from the
阳离子Ru-H配合物[(C 6 H 6 )(PCy 3 )(CO)RuH] + BF 4 - ( 1 )被发现是酚类和醛类脱水C-H偶联反应生成的有效催化剂2-烷基苯酚产品。酚类与支链醛的偶联反应选择性地形成1,1-二取代苯并呋喃,而与水杨醛的偶联反应产生呫吨衍生物。从 3-甲氧基苯酚与苯甲醛和 2-丙醇/2-丙醇-d 8 ( k H / k D ) 的偶联反应中观察到正常的氘同位素效应= 2.3 ± 0.3)。在 3-甲氧基苯酚与 4-甲氧基苯甲醛 (C(3) 1.021(3)) 偶联反应的烷基化产物的苄基碳以及与4-三氟苯甲醛 (C(2) 1.017(3)、C(3) 1.011(2))。来自 3-甲氧基苯酚与对位取代苯甲醛p -XC 6 H 4 CHO (X = OMe, Me, H, F, Cl, CF 3 ) 的偶联反应的 Hammett 图显示了 V 形线性斜率。通过 NMR 从1