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• 122-00-9 para-methylacetophenone 
• 100-51-6 benzyl alcohol 
• 536-50-5 CH₃C₆H₄CH(CH₃)OH 
• 104-53-0 3-phenyl-propionaldehyde 
• 5720-05-8 4-methylphenylboronic acid 
• 5084-80-0 tri(4-tolyl)boroxine 
• 4224-96-8 3-phenyl-1-p-tolylprop-2-en-1-one 
• 14802-30-3 (E)-1-(4-methylphenyl)-3-phenyl-2-propen-1-one 
• 58824-48-9 1-(4-methylphenyl)-2-propen-1-ol 
• 591-50-4 iodobenzene 
• 5012-90-8 4-methylphenyl phenethyl ketone 
• 91-01-0 1,1-Diphenylmethanol 
• 100-52-7 benzaldehyde 

Relevant academic research and scientific papers

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.

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.

One pot tandem dual CC and CO bond reductions in the β-alkylation of secondary alcohols with primary alcohols by ruthenium complexes of amido and picolyl functionalized N-heterocyclic carbenes

Two different classes of ruthenium complexes, namely, [1-mesityl-3-(2,6-Me2-phenylacetamido)-imidazol-2-ylidene]Ru(p-cymene)Cl (1c) and {[1-(pyridin-2-ylmethyl)-3-(2,6-Me2-phenyl)-imidazol-2-ylidene]Ru(p-cymene)Cl}Cl (2c), successfully catalyzed the one-pot tandem alcohol-alcohol coupling reactions of a variety of secondary and primary alcohols, in moderate to good yields of ca. 63-89%. The mechanistic investigation performed on two representative catalytic substrates, 1-phenylethanol and benzyl alcohol using the neutral ruthenium (1c) complex showed that the catalysis proceeded via a partially reduced CC hydrogenated carbonyl species, [PhCOCH2CH2Ph] (3′), to the fully reduced CO and CC hydrogenated secondary alcohol, [PhCH(OH)CH2CH2Ph] (3). Furthermore, the time dependent study showed that the major product of the catalysis modulated between (3′) and (3) during the catalysis run performed over an extended period of 120 hours. Finally, the practical utility of the alcohol-alcohol coupling reaction was demonstrated by preparing five different flavan derivatives (13-17) related to various bioactive flavonoid natural products, in a one-pot tandem fashion.

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.

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.

Room-Temperature Guerbet Reaction with Unprecedented Catalytic Efficiency and Enantioselectivity

We report herein an unprecedented highly efficient Guerbet-type reaction at room temperature (catalytic TON up to >6000). This β-alkylation of secondary methyl carbinols with primary alcohols has significant advantage of delivering higher-order secondary alcohols in an economical, redox-neutral fashion. In addition, the first enantioselective Guerbet reaction has also been achieved using a commercially available chiral ruthenium complex to deliver secondary alcohols with moderate yield and up to 92 % ee. In both reactions, the use of a traceless ketone promoter proved to be beneficial for the catalytic efficiency.

Transition metal complexes of a bis(carbene) ligand featuring 1,2,4-triazolin-5-ylidene donors: structural diversity and catalytic applications

Dialkylation of the 1,3-bis(1,2,4-triazol-1-yl)benzene with ethyl bromide results in the formation of [L-H2]Br2which, upon salt metathesis with NH4PF6, readily yields the bis(triazolium) salt [L-H2](PF6)2with non-coordinating counterions. [L-H2](PF6)2and Ag2O react in a 1?:?1 ratio to yield a binuclear AgI-tetracarbene complex of the composition [(L)2Ag2](PF6)2which undergoes a facile transmetalation reaction with [Cu(SMe2)Br] to deliver the corresponding CuI-NHC complex [(L)2Cu2](PF6)2. In contrast, the [L-H2]Br2reacts with [Ir(Cp*)Cl2]2to generate a doubly C-H activated IrIII-NHC complex5. Similarly, the triazolinylidene donor supported diorthometalated RuII-complex6is also obtained. Complexes5and6represent the first examples of a stable diorthometalated binuclear IrIII/RuII-complex supported by 1,2,4-triazolin-5-ylidene donors. The synthesized IrIII-NHC complex5is found to be more effective than its RuII-analogue (6) for the reduction of a range of alkenes/alkynesviathe transfer hydrogenation strategy. Conversely, RuII-complex6is identified as an efficient catalyst (0.01 mol% loading) for the β-alkylation of a wide range of secondary alcohols using primary alcohols as alkylating partnersviaa borrowing hydrogen strategy.

Chelate ring size effects of Ir(P,N,N) complexes: Chemoselectivity switch in the asymmetric hydrogenation of α,β-unsaturated ketones

A novel, highly modular approach has been developed for the synthesis of new chiral P,N,N ligands with the general formula Ph2P(CH3)CH(CH2)mCH(CH3)NHCH2CH2(CH2)nN(CH3)2 and Ph2P(CH3)CHCH2CH(CH3)NHCH2(CH2)n-2-Py (m, n = 0, 1). The systematic variation of their P–N and N–N backbone led to the conclusion that the activity, chemo- and enantioselectivity in the hydrogenation of α,β-unsaturated ketones are highly dependent on the combination of the two bridge lengths. It has been found that a minor change in the ligand's structure, i. e. varying the value of m from 1 to 0, can switch the chemoselectivity of the reaction, from 80percent C[dbnd]O to 97percent C[dbnd]C selectivity.

C-C coupling formation using nitron complexes

A series of RuII (1), RhIII (2), IrIII (3, 4), IrI (5) and PdII (6-9) complexes of the 'instant carbene' nitron were prepared and characterized by 1H- and 13C-NMR, FT-IR and elemental analysis. The molecular structures of complexes 1-4 and 6 were determined by X-ray diffraction studies. The catalytic activity of the complexes (1-9) was evaluated in alpha(α)-alkylation reactions of ketones with alcohol via the borrowing hydrogen strategy under mild conditions. These complexes were able to perform this catalytic transformation in a short time with low catalyst and base amounts under an air atmosphere. Also, the PdII-nitron complexes (6-9) were applied in the Suzuki-Miyaura C-C coupling reaction and these complexes successfully initiated this reaction in a short time (30 minutes) using the H2O/2-propanol (1.5?:?0.5) solvent system. The DFT calculations revealed that the Pd0/II/0 pathway was more preferable for the mechanism