Ruthenium-Catalyzed β-Alkylation of Secondary Alcohols and α-Alkylation of Ketones via Borrowing Hydrogen: Dramatic Influence of the Pendant <i>N</i>-Heterocycle

Zhang, Chong; Zhao, Jiong‐Peng; Hu, Bowen; Shi, Jing; Chen, Dafa

doi:10.1021/acs.organomet.8b00847

Cited by 66 publications

(37 citation statements)

References 75 publications

(42 reference statements)

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“…Complexes 4 , 5 , 6 , and 8 do exhibit good activity for the catalysis, whereas [Cp*IrCl 2 ] 2 and [Cp*Ir(bpy)Cl]Cl show poor activity in this alkylation, clearly indicating the necessity of the naphthyridine‐pyridine ligand. To our disappointment, the reactivity of 8 appears to be superior to other naphthyridine‐pyridine complexes 4 , 5 , and 6 , indicating that the extra pendant functionality does not have the directing effect in the reactions …”

Section: Resultssupporting

confidence: 92%

Naphthyridine‐based iridium complexes: Structures and catalytic activity on alkylation of aryl ketones

Chen

Liu

2019

J Chinese Chemical Soc

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Iridium(III) complexes containing a designed ligand, 2‐amino‐7‐(2‐pyridinyl)‐1,8‐naphthyridine derivative, were prepared and all complexes were characterized using spectroscopic and crystallographic methods. These new Ir(III) complexes are able to act as catalysts for the C‐alkylation of aryl alkyl ketones with the use of alcohols as the alkylating agent. Typically, acetophenone undergoes alkylation with methanol and ethanol to yield isobutyrophenone and butyrophenone, respectively.

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Section: Resultssupporting

confidence: 92%

Naphthyridine‐based iridium complexes: Structures and catalytic activity on alkylation of aryl ketones

Chen

Liu

2019

J Chinese Chemical Soc

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“…3‐(3‐chlorophenyl)‐1‐phenylpropan‐1‐one (3 fa) Yield 208 mg 85 % (Catalyst Ru1 ), 212.9 mg 87 % (Catalyst Ru2 ); 1 H NMR (400 MHz, CDCl 3 ) δ 7.95 (d, J =8.2 Hz, 2H), 7.56 (t, J =7.4 Hz, 1H), 7.45 (t, J =7.6 Hz, 2H), 7.24 (t, J =2.8 Hz, 1H), 7.18–7.12 (m, 2H), 3.29 (t, J =7.6 Hz, 2H), 3.04 (t, J =7.6 Hz, 2H). 13 C NMR (101 MHz, CDCl 3 ) δ 198.79, 143.44, 136.79, 134.31, 133.30, 129.87, 128.75, 128.12, 126.81, 126.47, 40.09, 29.74.…”

Section: Methodsmentioning

confidence: 99%

Efficient Organoruthenium Catalysts for α‐Alkylation of Ketones and Amide with Alcohols: Synthesis of Quinolines via Hydrogen Borrowing Strategy and their Mechanistic Studies

Maji

Singh

et al. 2020

ChemCatChem

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A new family of phosphine free organometallic ruthenium(II) catalysts (Ru1–Ru4) supported by bidentate NN Schiff base ligands (L1–L4 where L1=N,N‐dimethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazineylidene)methyl) aniline, L2=N,N‐diethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazineylidene)methyl)aniline, L3=N,N‐dimethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐yl)hydrazineylidene)methyl)‐ aniline and L4=N,N‐diethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐yl)hydrazineylidene)methyl) aniline) was prepared and characterized. These half‐sandwich complexes acted as catalysts for C−C bond formation and exhibited excellent performance in the dehydrogenative coupling of ketones and amides. In the synthesis of C–C bonds, alcohols were utilized as the alkylating agent. A broad range of substrates, including sterically hindered ketones and alcohols, were well tolerated under the optimized conditions (TON up to 47000 and TOF up to 11750 h−1). This ruthenium (II) catalysts were also active towards the dehydrogenative cyclization of o‐amino benzyl alcohol for the formation of quinolines derivatives. Various polysubstituted quinolines were synthesized in moderate to excellent yields (TON up to 71000 and TOF up to 11830 h−1). Control experiments were carried out and the ruthenium hydride intermediate was characterized to support the reaction mechanism and a probable reaction pathway of dehydrogenative coupling for the C−C bond formation has been proposed.

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“…3‐(3‐Bromo‐phenyl)‐1‐phenyl‐propan‐1‐one (3 na) : [31] White solid. Yield: 256.4 mg, 89 %, mp 69–70 °C.…”

Section: Methodsmentioning

confidence: 99%

“…Yield: 207.6 mg, 91 %. 1 3-(4-Fluoro-phenyl)-1-phenyl-propan-1-one (3 ka): [31] Colorless oil. Yield: 216.7 mg, 95 %.…”

Section: General Procedures For Catalytic Cyclementioning

confidence: 99%

Iridium Complexes as Efficient Catalysts for Construction of α‐Substituted Ketones via Hydrogen Borrowing of Alcohols in Water

et al. 2021

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Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes‐catalyzed cross‐coupling of alcohols via hydrogen borrowing, affording a series of α‐alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram‐scale experiment demonstrates this methodology of iridium‐catalyzed cross‐coupling of alcohols has potential application in the practical synthesis of α‐alkylated ketones.

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Ruthenium-Catalyzed β-Alkylation of Secondary Alcohols and α-Alkylation of Ketones via Borrowing Hydrogen: Dramatic Influence of the Pendant N-Heterocycle

Cited by 66 publications

References 75 publications

Naphthyridine‐based iridium complexes: Structures and catalytic activity on alkylation of aryl ketones

Naphthyridine‐based iridium complexes: Structures and catalytic activity on alkylation of aryl ketones

Efficient Organoruthenium Catalysts for α‐Alkylation of Ketones and Amide with Alcohols: Synthesis of Quinolines via Hydrogen Borrowing Strategy and their Mechanistic Studies

Iridium Complexes as Efficient Catalysts for Construction of α‐Substituted Ketones via Hydrogen Borrowing of Alcohols in Water

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