page_title: Murai reaction
section_title: Ru(II) catalysts
hierarchical_section_title: Murai reaction / Mechanism / Ru(II) catalysts
caption_attribution_description: English: Proposed mechanism of the reaction catalyzed by [Ru(H)2(H2)2(PR3)2] between acetophenone and ethylene. Spectator ligands (PMe3) omitted for clarity.
context_page_description: The Murai reaction is an organic reaction that uses C-H activation to create a new C-C bond between a terminal or strained internal alkene and an aromatic compound using a ruthenium catalyst. The reaction, named after Shinji Murai, was first reported in 1993. While not the first example of C-H activation, the Murai reaction is notable for its high efficiency and scope. Previous examples of such hydroarylations required more forcing conditions and narrow scope.
context_section_description: The complex [Ru(o-C₆H₄PPh₂)(H)(CO)(PPh₃)₂] catalyzes the Murai reaction at room temperature. For [Ru(H)₂(H₂)₂(PR₃)₂], the active complex is [Ru(H)₂(PR₃)₂].
  After the active form of the ruthenium catalyst complex is generated from 1, acetophenone coordinates to the complex via its carbonyl oxygen and agostically via its ortho C-H bond (2). As in the Ru⁰ proposed mechanism, this agostic interaction leads to the oxidative addition of the ortho C-H. Reductive elimination releases H₂, which remains coordinated, giving complex 3. Coordination of ethylene and decoordination of the ketone results in complex 4 which then undergoes migratory insertion of ethylene into the hydride to give 5. Following oxidative addition of H₂ (6), the complex reductively eliminates the product to give the product agostically bound to the complex. Coordination of another acetophenone molecule regenerates complex 2.
caption: Mechanism proposed for the reaction acetophenone and ethylene as catalyzed by [Ru(H)2(H2)2(PR3)2]. Spectator ligands (PMe3) omitted for clarity.
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