56345-34-7Relevant academic research and scientific papers
A Proton-Responsive Pyridyl(benzamide)-Functionalized NHC Ligand on Ir Complex for Alkylation of Ketones and Secondary Alcohols
Kaur, Mandeep,U Din Reshi, Noor,Patra, Kamaless,Bhattacherya, Arindom,Kunnikuruvan, Sooraj,Bera, Jitendra K.
supporting information, p. 10737 - 10748 (2021/06/15)
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.
Selective C-alkylation Between Alcohols Catalyzed by N-Heterocyclic Carbene Molybdenum
Liu, Jiahao,Li, Weikang,Li, Yinwu,Liu, Yan,Ke, Zhuofeng
supporting information, p. 3124 - 3128 (2021/09/20)
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
Ding, Keying,Pandey, Bedraj,Xu, Shi
supporting information, p. 1207 - 1212 (2021/05/29)
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.
Room-Temperature Guerbet Reaction with Unprecedented Catalytic Efficiency and Enantioselectivity
Lau, Kai Kiat,Liao, Gang,Ng, Teng Wei,Pan, Hui-Jie,Zhao, Yu
supporting information, p. 11384 - 11389 (2020/06/02)
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.
Ruthenium-Catalyzed β-Alkylation of Secondary Alcohols and α-Alkylation of Ketones via Borrowing Hydrogen: Dramatic Influence of the Pendant N-Heterocycle
Zhang, Chong,Zhao, Jiong-Peng,Hu, Bowen,Shi, Jing,Chen, Dafa
, p. 654 - 664 (2019/02/17)
Three bidentate ruthenium(II) complexes with a pyridonate fragment were prepared and fully characterized. These complexes are structurally similar, but differ in their pendant substituents. Complex 1 contains a phenyl unit, whereas complexes 2 and 3 have uncoordinated thienyl and thiazolyl groups, respectively. These complexes were tested as catalysts for β-alkylation of secondary alcohols with primary alcohols, and 3 shows the highest activity, suggesting the thiazolyl ring participates in the catalytic process. Furthermore, 3 is an excellent catalyst for α-alkylation of ketones with primary alcohols. Various α-alkylated ketones were synthesized in high yields, by using 0.05 mol % 3 and 0.25 equiv of t-BuOK within 30 min.
Unusual C-O bond cleavage of aromatic ethers in ruthenium complexes bearing a 2-alkoxypyridyl fragment
Deng, Danfeng,Hu, Bowen,Yang, Min,Chen, Dafa
supporting information, p. 13614 - 13621 (2019/09/30)
Two tetradentate (NNOP) ruthenium products [{RO-C5H3N-C5H3N-CH(O)-C6H4-PPh2}Ru(CO)(PPh3)]Cl (1: R = Me; 3: R = Ph) were isolated by the reactions of the corresponding ligands with RuHCl(PPh3)3(CO). Complex 1 could also be transformed into 2 when heated in THF, through C-OMe bond cleavage. The mechanism of the unusual C-O cleavage in complex 1 was investigated, and the results indicate that it is an SN2 mechanism through the attack of trace amounts of neutral H2O. In contrast, in the presence of KOH, the reaction switches to an SNAr chemistry. The bidentate ruthenium isomers [{CH3O-C5H3N-C5H4N}RuH(CO)(PPh3)2]Cl (4a and 4b) could undergo similar C-O cleavage, affording product {O-C5H3N-C5H4N}RuH(CO)(PPh3)2 (5), which reacted with HCl to generate complex [{HO-C5H3N-C5H4N}RuH(CO)(PPh3)2]Cl (6). These complexes were tested as catalysts for β-alkylation of secondary alcohols with primary alcohols, and a series of β-alkylated 1-phenylethanol derivatives were isolated in high yields.
Sodium amalgam mediated desulfonylative reduction of α-functionalized β-ketosulfones
Chan, Chieh-Kai,Huang, Yi-Hsuan,Chang, Meng-Yang
, p. 5521 - 5529 (2016/08/04)
Sodium amalgam mediated desulfonylative reduction of β-ketosulfones in MeOH at rt affords alcohols in good yields via radical desulfonylation of β-ketosulfones and sequential Bouveault-Blanc reduction of the resulting ketones.
The method of manufacturing the same
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Paragraph 0061-0065, (2017/02/02)
PROBLEM TO BE SOLVED: To provide a method for producing a dimer which can obtain the dimer even in the absence of a specific transition metal such as Ir. SOLUTION: The method for producing a dimer comprises dimerizing an alcohol (1) (wherein R1and R2are each hydrogen or a monovalent hydrocarbon group) and an alcohol (2) (wherein R3and R4are each hydrogen or a monovalent hydrocarbon group) or a carbonyl compound (3) (wherein R3and R4are the same as defined above) in the presence of an alkali metal or an alkali metal base and in the absence of a transition metal. COPYRIGHT: (C)2011,JPOandINPIT
Ruthenium-catalyzed β-alkylation of secondary alcohols with primary alcohols
Bai, Wei,Jia, Guochen
, p. 234 - 241 (2015/06/02)
The catalytic properties of a series of ruthenium complexes for β-alkylation of secondary alcohols with primary alcohols were studied. The catalytic activities of the ruthenium complexes were found to be dependent on the auxiliary ligands. The most active catalytic precursor found in this study is the ruthenium complex RuCl2(PPh3)2(2-NH2CH2Py) [2-NH2CH2Py = 2-aminomethyl pyridine], which effectively catalyzed the β-alkylation of both aryl- and alkyl-substituted secondary alcohols with benzylic and alkyl primary alcohols.
Catalyst-free dehydrative α-alkylation of ketones with alcohols: Green and selective autocatalyzed synthesis of alcohols and ketones
Xu, Qing,Chen, Jianhui,Tian, Haiwen,Yuan, Xueqin,Li, Shuangyan,Zhou, Chongkuan,Liu, Jianping
, p. 225 - 229 (2014/01/17)
Direct dehydrative α-alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst-free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one-pot manner and on a large scale by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Plain and simple: The title reaction has been realized under simple and practical conditions without using external catalysts, and can afford alkylated ketone or alcohol products in a one-pot manner and on a large scale. The reaction proceeds by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Copyright
