Solvent-free ruthenium-catalysed triflate coupling as a convenient method for selective azole-o-C-H monoarylation.

Metal-catalysed ortho-directed C-H functionalization usually faces selectivity issues in the competition between mono- and disubstitution processes. We report herein the ruthenium-catalysed N-directed C-H monoarylation of arylpyrazoles with a selectivity of up to 96% or that generally reaches values above 80%. This selectivity is an effect of solvent-free conditions associated with sulfonate reagents, in the absence of frequently used acidic additives.

[1]  V. Guerchais,et al.  Reactivity of 4-phenylthiazoles in ruthenium catalyzed direct arylations , 2019, Applied Organometallic Chemistry.

[2]  K. S. Singh,et al.  Recent Advances in C–H Bond Functionalization with Ruthenium-Based Catalysts , 2019, Catalysts.

[3]  I. Vitorica-Yrezabal,et al.  Cyclometallated ruthenium catalyst enables late-stage directed arylation of pharmaceuticals , 2018, Nature Chemistry.

[4]  Jean‐Cyrille Hierso,et al.  Phenol Derivatives in Ruthenium-Catalyzed C-H Arylation: A General Synthetic Access to Azole-Based Congested Polyaromatics , 2018, European Journal of Organic Chemistry.

[5]  F. Jordan,et al.  Recent Developments in Ruthenium-Catalyzed C–H Arylation: Array of Mechanistic Manifolds , 2017 .

[6]  I. Larrosa,et al.  Ruthenium‐Catalyzed C−H Arylation of Benzoic Acids and Indole Carboxylic Acids with Aryl Halides , 2016, Chemistry.

[7]  D. Weix,et al.  Ruthenium-Catalyzed C–H Arylation of Diverse Aryl Carboxylic Acids with Aryl and Heteroaryl Halides , 2016, Organic letters.

[8]  L. Ackermann,et al.  Amino Acid Ligands for Ruthenium(II)‐Catalyzed C–H Arylation of Aryltetrazoles with Chlorides: Expedient Access to Antihypertension Drugs , 2016 .

[9]  John D. Hayler,et al.  Updating and further expanding GSK's solvent sustainability guide , 2016 .

[10]  Gao-Feng Zha,et al.  Ruthenium-catalyzed direct arylations with aryl chlorides , 2016 .

[11]  Zhen-yuan Xu,et al.  Mild and versatile nitrate-promoted C-H bond fluorination. , 2014, Angewandte Chemie.

[12]  Y. Kobayashi,et al.  Regioselective Monoarylation of 2-Phenylbenzimidazole via Ruthenium-Catalyzed­ C–H Bond Functionalization , 2014 .

[13]  J. Gimeno,et al.  One-pot direct C-H arylation of arenes in water catalysed by RuCl3·nH2O-NaOAc in the presence of Zn. , 2013, Chemical communications.

[14]  I. Marek,et al.  Carboxylate-assisted ruthenium(II)-catalyzed C–H arylations of 5-aryl tetrazoles: step-economical access to Valsartan , 2013 .

[15]  C. Bruneau,et al.  Ruthenium(II)-catalyzed selective monoarylation in water and sequential functionalisations of C–H bonds , 2013 .

[16]  F. Glorius,et al.  Beyond directing groups: transition-metal-catalyzed C-H activation of simple arenes. , 2012, Angewandte Chemie.

[17]  J. Pospech,et al.  Well-defined ruthenium(II) carboxylate as catalyst for direct C-H/C-O bond arylations with phenols in water. , 2012, Organic letters.

[18]  T. Ritter,et al.  Catalysis for fluorination and trifluoromethylation , 2011, Nature.

[19]  L. Ackermann.  Carboxylate-assisted transition-metal-catalyzed C-H bond functionalizations: mechanism and scope. , 2011, Chemical reviews.

[20]  L. Ackermann,et al.  Mechanistic insight into direct arylations with ruthenium(II) carboxylate catalysts. , 2010, Organic letters.

[21]  K. Kirk.  Fluorination in Medicinal Chemistry: Methods, Strategies, and Recent Developments , 2008 .

[22]  L. Ackermann,et al.  Catalytic arylation reactions by C-H bond activation with aryl tosylates. , 2006, Angewandte Chemie.

[23]  Y. Inoue,et al.  Ruthenium complex catalyzed direct ortho arylation and alkenylation of aromatic imines with organic halides. , 2001, Organic letters.