62056-11-5

Upstream product

• 1669-55-2 1-(4-methylphenyl)-3-phenyl-1-propen-3-ol 
• 22252-14-8 (E)-3-(4-methylphenyl)-1-phenyl-2-propen-1-one 
• 589-18-4 4-Methylbenzyl alcohol 
• 98-85-1 1-Phenylethanol 
• 4224-87-7 4-methyl-chalcone 
• 88330-56-7 2-Methyl-5-phenyl-3-p-tolyl-isoxazolidine 
• 104-87-0 4-methyl-benzaldehyde 
• 98-86-2 acetophenone 

Downstream Products

• 43008-81-7 1-methyl-4-(3-phenylpropyl)benzene 
• 134539-86-9 1-methyl-4-(3-phenyl-2-propen-1-yl)benzene 
• 1669-50-7 1-phenyl-3-(4-tolyl)propan-1-one 

Relevant academic research and scientific papers

Bimetallic Pt–Sn/γ-Al2O3catalyzed β-alkylation of secondary alcohols with primary alcohols under solvent-free conditions

Heterogeneous bimetallic Pt–Sn/γ-Al2O3(0.5?wt% Pt, molar ratio Pt:Sn?=?1:3) was successfully utilized as the catalyst for direct β-alkylation of secondary alcohols with primary alcohols under solvent-free conditions. β-Alkylated secondary alcohols were obtained in moderate to high yields with water formed as the by-product through a hydrogen borrowing pathway. The present protocol provides a concise atom-economical and environmentally benign method for C–C bond formation.

Electronically tuneable orthometalated RuII–NHC complexes as efficient catalysts for C–C and C–N bond formations via borrowing hydrogen strategy

The catalytic activities of a series of simple and electronically tuneable cyclometalated RuII–NHC complexes (2a–d) were explored in various C–C/N bond formations following the borrowing hydrogen process. Slight modifications in the ligand backbone were noted to tune the activities of these complexes. Among them, the complex 2d featuring a 1,2,4-triazolylidene donor with a 4-NO2–phenyl substituent displayed the highest activity for the coupling of diverse secondary and primary alcohols with a low catalyst loading of 0.01 mol% and a sub-stoichiometric amount of inexpensive KOH base. The efficacy of this simple system was further showcased in the challenging one-pot unsymmetrical double alkylation of secondary alcohols using different primary alcohols. Moreover, the complex 2d also effectively catalyses the selective mono-N-methylation of various aromatic and aliphatic primary amines using methanol to deliver a range of N-methyl amines. Mechanistically, the β-alkylation reaction follows a borrowing hydrogen pathway which was established by the deuterium labelling experiment in combination with various control experiments. Intriguingly, in situ1H NMR and ESI-MS analyses evidently suggested the involvement of a Ru–H species in the catalytic cycle and further, the kinetic studies revealed a first order dependence of the reaction rate on the catalyst as well as the alcohol concentrations.

A Proton-Responsive Pyridyl(benzamide)-Functionalized NHC Ligand on Ir Complex for Alkylation of Ketones and Secondary Alcohols

A Cp*Ir(III) complex (1) of a newly designed ligand L1 featuring a proton-responsive pyridyl(benzamide) appended on N-heterocyclic carbene (NHC) has been synthesized. The molecular structure of 1 reveals a dearomatized form of the ligand. The protonation of 1 with HBF4 in tetrahydrofuran gives the corresponding aromatized complex [Cp*Ir(L1H)Cl]BF4 (2). Both compounds are characterized spectroscopically and by X-ray crystallography. The protonation of 1 with acid is examined by 1H NMR and UV-vis spectra. The proton-responsive character of 1 is exploited for catalyzing α-alkylation of ketones and β-alkylation of secondary alcohols using primary alcohols as alkylating agents through hydrogen-borrowing methodology. Compound 1 is an effective catalyst for these reactions and exhibits a superior activity in comparison to a structurally similar iridium complex [Cp*Ir(L2)Cl]PF6 (3) lacking a proton-responsive pendant amide moiety. The catalytic alkylation is characterized by a wide substrate scope, low catalyst and base loadings, and a short reaction time. The catalytic efficacy of 1 is also demonstrated for the syntheses of quinoline and lactone derivatives via acceptorless dehydrogenation, and selective alkylation of two steroids, pregnenolone and testosterone. Detailed mechanistic investigations and DFT calculations substantiate the role of the proton-responsive ligand in the hydrogen-borrowing process.

Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure

Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).

Nickel-catalyzed guerbet type reaction: C-alkylation of secondary alcohols via double (de)hydrogenation

Acceptorless double dehydrogenative cross-coupling of secondary and primary alcohols under nickel catalysis is reported. This Guerbet type reaction provides an atom- and a step-economical method for the C-alkylation of secondary alcohols under mild, benign conditions. A broad range of substrates including aromatic, cyclic, acyclic, and aliphatic alcohols was well tolerated. Interestingly, the C-alkylation of cholesterol derivatives and the double C-alkylation of cyclopentanol with various alcohols were also demonstrated.

Selective C-alkylation Between Alcohols Catalyzed by N-Heterocyclic Carbene Molybdenum

The first implementation of a molybdenum complex with an easily accessible bis-N-heterocyclic carbene ligand to catalyze β-alkylation of secondary alcohols via borrowing-hydrogen (BH) strategy using alcohols as alkylating agents is reported. Remarkably high activity, excellent selectivity, and broad substrate scope compatibility with advantages of catalyst usage low to 0.5 mol%, a catalytic amount of NaOH as the base, and H2O as the by-product are demonstrated in this green and step-economical protocol. Mechanistic studies indicate a plausible outer-sphere mechanism in which the alcohol dehydrogenation is the rate-determining step.

Switchable β-alkylation of secondary alcohols with primary alcohols by a well-defined cobalt catalyst

β-alkylation of secondary alcohols with primary alcohols to selectively generate alcohols by a well-defined Co catalyst is presented. Remarkably, a low catalyst loading of 0.7 mol % can be employed for the reaction. More significantly, this study represents the first Co-catalyzed switchable alcohol/ketone synthesis by simply manipulating the reaction parameters. In addition, the transformation is environmentally friendly, with water as the only byproduct.

Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

We report here the synthesis and characterization of a series of NNN pincer-nickel complexes of the type (R2NNN)NiCl2(CH3CN) (R = iPr, tBu, Cy, Ph, and p-F-C6H4) 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 = iPr, we report the crystal structure of the latter in this study for R = p-F-C6H4. 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 (Ph2NNN)NiCl2(CH3CN) and 5 mol % of NaOtBu 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.

Phosphine-free pincer-ruthenium catalyzed biofuel production: High rates, yields and turnovers of solventless alcohol alkylation

Phosphine-free pincer-ruthenium carbonyl complexes based on bis(imino)pyridine and 2,6-bis(benzimidazole-2-yl) pyridine ligands have been synthesized. For the β-alkylation of 1-phenyl ethanol with benzyl alcohol at 140 °C under solvent-free conditions, (Cy2NNN)RuCl2(CO) (0.00025 mol%) in combination with NaOH (2.5 mol%) was highly efficient (ca. 93% yield, 372?000 TON at 12?000 TO h-1). These are the highest reported values hitherto for a ruthenium based catalyst. The β-alkylation of various alcohol combinations was accomplished with ease which culminated to give 380?000 TON at 19?000 TO h-1 for the β-alkylation of 1-phenyl ethanol with 3-methoxy benzyl alcohol. DFT studies were complementary to mechanistic studies and indicate the β-hydride elimination step involving the extrusion of acetophenone to be the overall RDS. While the hydrogenation step is favored for the formation of α-alkylated ketone, the alcoholysis step is preferred for the formation of β-alkylated alcohol. The studies were extended for the upgradation of ethanol to biofuels. Among the pincer-ruthenium complexes based on bis(imino)pyridine, (Cy2NNN)RuCl2(CO) provided high productivity (335 TON at 170 TO h-1). Sterically more open pincer-ruthenium complexes such as (Bim2NNN)RuCl2(CO) based on the 2,6-bis(benzimidazole-2-yl) pyridine ligand demonstrated better reactivity and gave not only good ethanol conversion (ca. 58%) but also high turnovers (ca. 2100) with a good rate (ca. 710 TO h-1). Kinetic studies indicate first order dependence on concentration of both the catalyst and ethanol. Phosphine-free catalytic systems operating with unprecedented activity at a very low base loading to couple lower alcohols to higher alcohols of fuel and pharmaceutical importance are the salient features of this report. This journal is

Asymmetric Guerbet Reaction to Access Chiral Alcohols

The first example of an asymmetric Guerbet reaction has been developed. Using commercially available, classic Noyori RuII-diamine-diphosphine catalysts, well-known in asymmetric hydrogenation, racemic secondary alcohols are shown to couple with primary alcohols in the presence of a base, affording new chiral alcohols with enantiomeric ratios of up to 99:1. Requiring no reducing agents, the protocol provides an easy, alternative route for the synthesis of chiral alcohols. Mechanistic studies reveal that the reaction proceeds via a Ru-catalyzed asymmetric hydrogen autotransfer process in concert with a base-promoted allylic alcohol isomerization.