Scope and Mechanistic Studies on the Ruthenium-Catalyzed Multicomponent Deaminative C–H Coupling Reaction of Phenols with Aldehydes and Enamines for the Formation of Xanthene and Dioxacyclic Derivatives
Scope and Mechanistic Studies on the Ruthenium-Catalyzed Multicomponent Deaminative C–H Coupling Reaction of Phenols with Aldehydes and Enamines for the Formation of Xanthene and Dioxacyclic Derivatives
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DOI：
10.1021/acscatal.3c01651
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发表时间：
2023-06
期刊：
影响因子：
12.9
通讯作者：
Nuwan Pannilawithana;M. Son;Donghun Hwang;M. Baik;Chae S. Yi
中科院分区：
文献类型：
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作者：
Nuwan Pannilawithana;M. Son;Donghun Hwang;M. Baik;Chae S. Yi
四核Ru-H配合物[(PCy3)(CO)RuH]4(O)(OH)2(1)与3,4,5,6-四氯-1,2-苯醌（L1）催化生成的催化体系介导了酚与醛和胺的多组分脱氨偶联反应，生成了杂蒽产物。苯酚与2-羟基苯甲醛和环胺的多组分C-H偶联反应有效地生成了三环1,3-二恶辛衍生物，而苯酚与2-羟基苯甲醛和三乙胺的类似偶联反应选择性地生成了双环1,5-二恶辛衍生物。密度泛函理论（DFT）计算建立了两种能量上可行的杂蒽产物形成机制途径，两种途径都将C-O键裂解步骤确定为周转率限制步骤。3,5-二甲氧基苯酚与烯胺和对取代苯甲醛-X- c6h4cho （X = OMe, Me， H, Cl, CF3）偶联反应的Hammett图显示斜率为负（ρ = - 0.98）。计算出的能量分析表明，通过C-O解理速率限制步骤的机制也有类似的趋势（ρ = - 0.59）。结合实验和DFT计算结果，支持了苯酚与醛的脱水C-H偶联，然后与烯胺的脱氨偶联反应形成杂蒽产物的机理路径。
Thein situgenerated catalytic system from the tetranuclear Ru–H complex [(PCy3)(CO)RuH]4(O)(OH)2(1) with 3,4,5,6-tetrachloro-1,2-benzoquinone (L1) has been found to mediate a multicomponent deaminative coupling reaction of phenols with aldehydes and enamines to form xanthene products. The multicomponent C–H coupling reaction of phenols with 2-hydroxybenzaldehydes and cyclic enamines efficiently installed the tricyclic 1,3-dioxacin derivatives, while the analogous coupling reaction of phenols with 2-hydroxybenzaldehydes and triethylamine selectively formed bicyclic 1,5-dioxacyclic derivatives. The density functional theory (DFT) calculations established two energetically viable mechanistic pathways for the formation of xanthene products, in which both pathways identified the C–O bond cleavage step as the turnover limiting step. A Hammett plot from the coupling reaction of 3,5-dimethoxyphenol with an enamine andpara-substituted benzaldehydesp-X-C6H4CHO (X = OMe, Me, H, Cl, CF3) showed a negative slope (ρ = −0.98). The calculated energy analysis showed a similar trend (ρ = −0.59) for the mechanism via the C–O cleavage rate-limiting step. The combined experimental and DFT computational results support a mechanistic path that involves the dehydrative C–H coupling of phenol with aldehyde, followed by the deaminative coupling reaction with an enamine in forming the xanthene product.