Nickel-Catalyzed Guerbet Type Reaction: C-Alkylation of Secondary Alcohols <i>via</i> Double (de)Hydrogenation

Babu, Reshma; Subaramanian, Murugan; Midya, Siba P.; Balaraman, Ekambaram

doi:10.1021/acs.orglett.1c00782

Cited by 60 publications

(21 citation statements)

References 56 publications

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“…Very recently, Balaraman reported excellent yields (up to 90%) in the β-alkylation of various alcohols using NiBr 2 (5 mol %)/TMEDA (5 mol %) in the presence of an equivalent of KOH using n -octane as solvent at 130 °C (Figure ). To the best of our knowledge, there are no other homogeneous Ni systems (none with pincer-Ni, , in particular) that have been reported for this reaction (Figure ).…”

Section: Introductionmentioning

confidence: 96%

Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

2021

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We report here the synthesis and characterization of a series of NNN pincer-nickel complexes of the type ( R2 NNN)-NiCl 2 (CH 3 CN) (R = i Pr, t Bu, Cy, Ph, and p-F-C 6 H 4 ) based on bis(imino)pyridine ligands. In solution, these complexes are found to be equilibrium mixtures containing one and two pincer ligands, respectively. While the crystal structure of the former was reported by us recently for R = i Pr, we report the crystal structure of the latter in this study for R = p-F-C 6 H 4 . The considered NNN pincer-Ni complexes have been successfully employed to accomplish the catalytic β-alkylation of several secondary alcohols with a variety of benzyl alcohols at 140 °C with high yields and unprecedented turnovers. A maximum of 92% yield of the β-alkylated product at 18 400 TON was obtained in the reaction of benzyl alcohol with 1-(4-(trifluoromethyl)phenyl)ethane-1-ol in the presence of 0.005 mol % of ( Ph2 NNN)NiCl 2 (CH 3 CN) and 5 mol % of NaO t Bu at 140 °C after 24 h. The reaction exhibits zero-order dependence of rate on catalyst concentration and first-order dependence on the concentration of base, benzyl alcohol, and 1-phenyl ethanol which points to the base-mediated aldol condensation as the rate-determining step. Most of the intermediates involved in catalysis have been identified by HRMS. To the best of our knowledge, this is the first report on a pincer-Ni catalyzed β-alkylation of alcohols and, hitherto, such unprecedented turnovers have not been reported with a homogeneous molecular nickel-based catalyst.

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Section: Introductionmentioning

confidence: 96%

Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

2021

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“…1-(4-chlorophenyl)-3-(4-methoxyphenyl)propan-1-ol (3be) [92] [a] 20 D = +6.9 (c 0.49, CH 2 Cl 2 ). Yield: 36% (49.8 mg) as a colorless oil; 1 H NMR (400 MHz, CDCl 3 ) δ 7.29 (q, J = 8.3, 4H), 7.09 (d, J = 8.2, 2H), 6.82 (d, J = 8.3, 2H), 4.64 (dd, J = 7.9, 5.3, 1H), 3.78 (s, 3H), 2.75-2.54 (m, 2H) and 2.12-1.88 (m, 3H).…”

Section: General Procedures For Asymmetric Addition Of Aliphatic Alde...mentioning

confidence: 99%

“…1-(p-tolyl)heptan-1-ol (3ea) [92] [a] The enantiomeric excess was determined by HPLC using Daicel Chiralpak AS-Hcolumn, hexane/i-PrOH 99:1, flow rate 1.0 mL/min, UV detection at 220 nm, t minor = 8.920 min, t major = 11.107 min and 93:7 er.…”

Section: General Procedures For Asymmetric Addition Of Aliphatic Alde...mentioning

confidence: 99%

Ru-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes via P-Chiral Monophosphorous Ligands

et al. 2022

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Chiral alcohols are among the most widely applied in fine chemicals, pharmaceuticals and agrochemicals. Herein, the Ru-monophosphine catalyst formed in situ was found to promote an enantioselective addition of aliphatic aldehydes with arylboronic acids, delivering the chiral alcohols in excellent yields and enantioselectivities and exhibiting a broad scope of aliphatic aldehydes and arylboronic acids. The enantioselectivities are highly dependent on the monophosphorous ligands. The utility of this asymmetric synthetic method was showcased by a large-scale transformation.

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“…Metal-catalyzed heterocoupling reactions of secondary and primary alcohols proceeds through controllable dehydrogenation-condensation-hydrogenation steps, selectively affording α,β-unsaturated ketones, α-alkylated ketones or β-alkylated secondary alcohols [9][10][11][12][13]. Various molecular complexes based on Ru [14][15][16][17], Ir [18][19][20][21], Co [22][23][24][25], Ni [26][27][28][29][30], and Mn [31][32][33][34][35][36] have been developed for these transformations. However, these are homogeneous catalysts and separation and recycling is an impediment to their large-scale industrial use.…”

Section: Introductionmentioning

confidence: 99%

Construction of a (NNN)Ru-Incorporated Porous Organic Polymer with High Catalytic Activity for β-Alkylation of Secondary Alcohols with Primary Alcohols

Cui

Wang

et al. 2022

Polymers

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Solid supports functionalized with molecular metal catalysts combine many of the advantages of heterogeneous and homogeneous catalysis. A (NNN)Ru-incorporated porous organic polymer (POP-bp/bbpRuCl3) exhibited high catalytic efficiency and broad functional group tolerance in the C–C cross-coupling of secondary and primary alcohols to give β-alkylated secondary alcohols. This catalyst demonstrated excellent durability during successive recycling without leaching of Ru which is ascribed to the strong binding of the pincer ligands to the metal ions.

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Nickel-Catalyzed Guerbet Type Reaction: C-Alkylation of Secondary Alcohols via Double (de)Hydrogenation

Cited by 60 publications

References 56 publications

Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

Ru-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes via P-Chiral Monophosphorous Ligands

Construction of a (NNN)Ru-Incorporated Porous Organic Polymer with High Catalytic Activity for β-Alkylation of Secondary Alcohols with Primary Alcohols

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