253785-28-3

Upstream product

• 67-56-1 methanol 
• 52462-29-0 [ruthenium(II)(η⁶-1-methyl-4-isopropyl-benzene)(chloride)(μ-chloride)]₂ 
• 2622-14-2 tricyclohexylphosphine 
• 145381-23-3 (p-cymene)RuCl2(PCy3) 
• 22092-92-8 diisopropopylaminoborane 
• 694-53-1 phenylsilane 

Relevant academic research and scientific papers

Ruthenium(II)-Catalyzed Regioselective 1,2-Hydrosilylation of N-Heteroarenes and Tetrel Bonding Mechanism

An efficient regioselective dearomatization of N-heteroarenes using a ruthenium precatalyst [Ru-(p-cymene)(PCy3)Cl2] 1 is achieved. Reactions were performed under mild and neat conditions. A wide variety of N-heteroarenes undergo the addition of silanes in the presence of precatalyst 1, leading to exclusive N-silyl-1,2-dihydroheteroarene products. This catalytic method displays a broad substrate scope; quinolines, isoquinolines, benzimidazoles, quinoxalines, pyrazines, pyrimidines, and pyridines undergo highly selective 1,2-dearomatization. Both electron-donating and electron-withdrawing substituents on N-heteroaromatics are well tolerated in this protocol. Mechanistic studies indicate the presence of [Ru-(p-cymene) (PCy3)HCl] 4 in the reaction mixture, which may be the resting state of the catalyst. The complete catalytic cycle as revealed from density functional theory (DFT) studies show that the product formation is governed by N → Si tetrel bonding. Initially, PCy3 dissociates from 1, and further reaction of [(p-cymene)RuCl2] 20 with silane generates the catalytically active intermediate [(p-cymene)RuHCl] 7. Heteroarene coordinates with 7, and subsequent dearomative 1,3-hydride transfer to the C2 position of the heteroaryl ligand generates an amide-ligated intermediate in which the reaction of silane occurs through a tetrel bonding and provides a selective pathway for 1,2-addition. DFT studies also revealed that ruthenium-catalyzed 1,4-hydroboration of pyridines is a facile process with a free energy barrier of 3.2 kcal/mol, whereas a pathway for the 1,2-hydroboration product is not observed due to the steric effects exerted by methyl groups on pinacolborane (HBpin) and p-cymene. Notably, enabled by the amine-amide inter-conversion of the coordinated heteroarene ligand, the +2 oxidation state of ruthenium intermediates remains unchanged throughout the catalytic cycle.

Ruthenium-Catalyzed Reductive Cleavage of Unstrained Aryl-Aryl Bonds: Reaction Development and Mechanistic Study

Cleavage of carbon-carbon bonds has been found in some important industrial processes, for example, petroleum cracking, and has inspired development of numerous synthetic methods. However, nonpolar unstrained C(aryl)-C(aryl) bonds remain one of the toughest bonds to be activated. As a detailed study of a fundamental reaction mode, here a full story is described about our development of a Ru-catalyzed reductive cleavage of unstrained C(aryl)-C(aryl) bonds. A wide range of biaryl compounds that contain directing groups (DGs) at 2,2′ positions can serve as effective substrates. Various heterocycles, such as pyridine, quinoline, pyrimidine, and pyrazole, can be employed as DGs. Besides hydrogen gas, other reagents, such as Hantzsch ester, silanes, and alcohols, can be employed as terminal reductants. The reaction is pH neutral and free of oxidants; thus a number of functional groups are tolerated. Notably, a one-pot C-C activation/C-C coupling has been realized. Computational and experimental mechanistic studies indicate that the reaction involves a ruthenium(II) monohydride-mediated C(aryl)-C(aryl) activation and the resting state of the catalyst is a η4-coordinated ruthenium(II) dichloride complex, which could inspire development of other transformations based on this reaction mode.

Aminoborane σ complexes: Significance of hydride co-ligands in dynamic processes and dehydrogenative borylene formation

Systems of the type [(p-cym)Ru(PR3)(H)(H2BN iPr2)]+ (R = Cy, Ph) can be synthesized from (p-cym)Ru(PR3)Cl2 and H2BNiPr 2/Na[BArf4] and are best formulated as (hydrido)ruthenium κ1-aminoborane complexes. VT-NMR measurements have been used to probe the σ-bond metathesis process leading to Ru-H/H-B exchange, yielding an activation barrier of ΔG ? = 7.5 kcal mol-1 at 161 K. Moreover, in contrast to the case for related non-hydride-containing systems, reactivity toward alkenes constitutes a viable route to a metal borylene complex via sacrificial hydrogenation.

Multifaceted chemistry of [(Cymene)RuCl2]2 and PCy3

The reaction of [(cymene)RuCl2]2 (1) with PCy 3 was investigated using different stoichiometries and reaction conditions. Whereas a mixture of complex 1 and 2 equiv of PCy3 in methanol gave the known adduct [(cy