14097-24-6Relevant articles and documents
Microwave-assisted solid reaction: Reduction of ketones using sodium borohydride
Chen, Same-Ting
, p. 509 - 511 (1999)
A general and efficient procedure for microwave-assisted reduction of liquid and solid ketones using sodium borohydride without solvents is described. The added support can enhance both the efficiency and chemoselectivity of reduction.
Mono and dimetallic pyrene-imidazolylidene complexes of iridium(III) for the deuteration of organic substrates and the C-C coupling of alcohols
Iba?ez,Poyatos,Peris
, p. 14154 - 14159 (2016)
Three different Ir(iii) complexes with pyrene-containing N-heterocyclic carbenes have been prepared and characterized. Two complexes contain a monodentate pyrene-imidazolylidene ligand, and have the formulae [IrCp?Cl2(pyrene-NHC)] and [IrCp?(CO3)(pyrene-NHC)]. The third complex is a dimetallic complex with a pyrene-di-imidazolylidene bridging ligand, with the formula [{IrCp?(CO3)}2(μ-pyrene-di-NHC)]. The catalytic activity of the three complexes was tested in the H/D exchange of organic substrates, and in the β-alkylation of 1-phenylethanol with primary alcohols. In the deuteration of organic substrates, the carbonate complexes are active even in the absence of additives. The dimetallic complex is the most active one in the catalytic coupling of alcohols, a result that may be interpreted as a consequence of the cooperativity between the two metal centres.
Nickel-catalysed three-component connection reaction of a phenyl group, conjugated dienes, and aldehydes: Stereoselective synthesis of (E)-5-phenyl-3-penten-1-ols and (E)-3-methyl-5-phenyl-3-penten-1-ols
Shibata, Kazufumi,Kimura, Masanari,Kojima, Keisuke,Tanaka, Shuji,Tamaru, Yoshinao
, p. 348 - 353 (2001)
In the presence of 10 mol% of Ni(acac)2, Ph2Zn reacts with 1,3-butadiene and aldehydes at room temperature to give 1-alkyl and 1-aryl substituted (E)-5-phenyl-3-penten-1-ols (3) in good yields. Under similar conditions, the three components of Ph3BZnEt2, isoprene, and aldehydes combine with each other to furnish 1-alkyl and 1-aryl substituted (E)-3-methyl-5-phenyl-3-penten-1-ols (5) in good yields.
Chemistry of ethanediyl S,S-acetals 9-asymmetric synthesis of chiral cis allylic alcohols
Caputo,Ferreri,Palumbo,Pedatella
, p. 1517 - 1522 (1995)
(2Z,1S)-1,3-diphenyl-2-propenol is obtained from the chiral 5,6-dihydro-1,4-dithiin 1b in two steps and 60% enantiomeric excess. Combining our previously reported stereoselective double bond formation and this 1,4 asymmetric induction introduces a new rou
Electronically tuneable orthometalated RuII–NHC complexes as efficient catalysts for C–C and C–N bond formations via borrowing hydrogen strategy
Illam, Praseetha Mathoor,Rit, Arnab
, p. 67 - 74 (2022/01/19)
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.
Reductive Arylation of Amides via a Nickel-Catalyzed Suzuki–Miyaura-Coupling and Transfer-Hydrogenation Cascade
Boit, Timothy B.,Mehta, Milauni M.,Kim, Junyong,Baker, Emma L.,Garg, Neil K.
supporting information, p. 2472 - 2477 (2020/12/03)
We report a means to achieve the addition of two disparate nucleophiles to the amide carbonyl carbon in a single operational step. Our method takes advantage of non-precious-metal catalysis and allows for the facile conversion of amides to chiral alcohols via a one-pot Suzuki–Miyaura cross-coupling/transfer-hydrogenation process. This study is anticipated to promote the development of new transformations that allow for the conversion of carboxylic acid derivatives to functional groups bearing stereogenic centers via cascade processes.
Transfer Hydrogenation of Flavanones and ortho-Hydroxychalcones to 1,3-Diarylpropanols Catalyzed by CNN Pincer Ruthenium Complexes
Soto, Martín,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto,Baratta, Walter
, p. 2152 - 2157 (2021/03/03)
The transfer hydrogenation of flavanones and ortho-hydroxychalcones catalyzed by ruthenium pincer complexes RuCl(CNNPh)(disphosphine) has allowed the synthesis of ortho-hydroxy 1,3-diarypropanols in 80–88 % yield, under mild reaction conditions and short reaction times (1 h) in 2-propanol. The amount of the co-catalyst NaOiPr has been found crucial for the selective reduction of flavanones to ortho-hydroxy 1,3-diarypropanols vs. flavan-4-ols. Preliminary results show that with pincer catalysts bearing (S,R)-Josiphos, flavanone is reduced to the corresponding (S)-alcohol in moderate conversion (36 %) and up to 92 % ee.
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.
Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
supporting information, p. 3090 - 3097 (2021/05/10)
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.).
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
Dey, Shreyata,Ghosh, Prasenjit,Prakasham, A. P.,Ta, Sabyasachi
supporting information, p. 15640 - 15654 (2021/11/30)
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.
