Raju Mandal, Subhendu Ghosh, Swastik Laha, Pritishree Panigrahi, Kalishankar Bhattacharyya* and Bhisma K. Patel*,
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引用次数: 0
摘要
通过脱羧自由基-自由基交叉偶联(C(sp2) -C (sp2))与肟酯,提出了ent介导的2-芳基喹啉的c3 - n -杂芳化反应。光活化后,光催化剂的三重态能量被转移到两个反应伙伴(肟酯和2-苯基喹啉)。被激发的肟酯发生脱羧裂解,形成c中心的n -杂芳基自由基和n中心的亚胺自由基。前者攻击喹诺啉二自由基的C3位点,而后者作为氢原子萃取剂(HAA)。计算研究表明,C-C键与杂芳基自由基的形成在能量上比C-N键的形成更有利。
A Mechanistic Perspective on Photocatalytic EnT-Enabled C3-N-Heteroarylation of Aryl Quinoxaline via C(sp2)–C(sp2) Coupling
An EnT-mediated C3-N-heteroarylation of 2-aryl quinoxalines via decarboxylative radical–radical cross-coupling (C(sp2)–C(sp2)) with oxime esters is presented. Upon photoactivation, the triplet energy of the photocatalyst is transferred to both reacting partners (oxime ester and 2-phenylquinoxaline). The excited oxime ester undergoes decarboxylative fragmentation to a C-centered N-heteroaryl radical and an N-centered imine radical. The former attacks the C3 site of the quinoxaline diradical, while the latter acts as a hydrogen atom abstractor (HAA). Computational studies revealed that C–C bond formation with the heteroaryl radical is energetically more favorable than C–N bond formation.
期刊介绍:
Organic Letters invites original reports of fundamental research in all branches of the theory and practice of organic, physical organic, organometallic,medicinal, and bioorganic chemistry. Organic Letters provides rapid disclosure of the key elements of significant studies that are of interest to a large portion of the organic community. In selecting manuscripts for publication, the Editors place emphasis on the originality, quality and wide interest of the work. Authors should provide enough background information to place the new disclosure in context and to justify the rapid publication format. Back-to-back Letters will be considered. Full details should be reserved for an Article, which should appear in due course.