Aromatic and olefinic C-H alkenylation by catalysis with spirocyclic NHC Ru(IV) pincer complex

• Published in: Science China. Chemistry Vol. 66; no. 10; pp. 2791 - 2796
• Main Authors: Cai, Heng, Tu, Yong-Qiang, Lu, Ka, Chen, Qi-Long, Zhang, Fu-Min, Zhang, Xiao-Ming, Pan, Yuan-Jiang, Yan, Zhi-Bo
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 01.10.2023; Science Press; Springer Nature B.V
• Subjects: Bromides; Catalysis; Catalysts; Chemical engineering; Chemistry; Chemistry and Materials Science; Chemistry, Multidisciplinary; Chemistry/Food Science; Dienes; Electron transfer; Electrons; Hydrocarbons; Oxidation; Physical Sciences; Ruthenium; Science & Technology; Single electrons; Transition metals; single electron transfer pathway; spirocyclic NHC-Ru pincer catalyst; C-H alkenylation; transitionmetal catalysis; unactivated alkenyl bromides and triflates; ROOM-TEMPERATURE; ACTIVATION; ALKYLATION; ARENES; DIRECT ARYLATIONS; RUTHENIUM CATALYST; FUNCTIONALIZATION; FLUOROARENES; OLEFINATION; HYDROARYLATION
• ISSN: 1674-7291; 1869-1870
• DOI: 10.1007/s11426-022-1541-5

Catalyst innovation lies at the heart of transition-metal-catalyzed reaction development. In this article, we have explored the C(sp 2 )—H alkenylation activity with novel spirocyclic N-heterocyclic carbene (NHC)-based cyclometalated ruthenium pincer catalyst system, SNRu-X . After screening catalyst and condition, a high valent Ru(IV) dioxide (X = O 2 ) species has demonstrated superior reactivity in the catalytic alkenylation of aromatic and olefinic C-H bonds with unactivated alkenyl bromides and triflates. This reaction has achieved the easy construction of a wide range of (hetero)aromatic alkenes and dienes, in good to excellent yields with exclusive selectivity. Preliminary mechanistic studies indicate that this reaction may proceed through a single electron transfer (SET) triggered oxidative addition, by doing so, providing valuable complementary to classical alke-nylation reactions that are dependent on activated alkenyl precursors.