7731-02-4Relevant academic research and scientific papers
Bifunctional Behavior of Unsaturated Intramolecular Phosphane-Borane Frustrated Lewis Pairs Derived from Uncatalyzed 1,4-Hydrophosphination of a Dienylborane
Chen, Guo-Qiang,Kehr, Gerald,Daniliuc, Constantin G.,Wibbeling, Birgit,Erker, Gerhard
, p. 12449 - 12455 (2015)
Three unsaturated C4-bridged phospane/borane frustrated Lewis pairs (P/B FLPs) are prepared by uncatalyzed hydrophosphination of a dienylborane. The systems are bifunctional. Consequently, two examples undergo clean hydroboration reactions with
Computational and experimental approach to the role of structure-directing agents in the synthesis of zeolites: The case of cyclohexyl alkyl pyrrolidinium salts in the synthesis of β, EU-1, ZSM-11, and ZSM-12 zeolites
Sastre, German,Leiva, Sandra,Sabater, Maria J.,Gimenez, Ignacio,Rey, Fernando,Valencia, Susana,Corma, Avelino
, p. 5432 - 5440 (2003)
The role of structure-directing agents (SDA) in the synthesis of zeolites is investigated, and the structures obtained in the synthesis are rationalized in terms of the energetic stabilization between the SDA and the microporous zeolite structure. An explanation is provided for the synthesis outcome in terms of a balance between kinetic and thermodynamic factors throughout the nucleation and crystallization stages. The stability of β, EU-1, ZSM-11, and ZSM-12 zeolites is calculated over a wide range of Si/Al ratios when cyclohexyl alkyl pyrrolidinium salts are used as the SDA. The role of the SDA allows us to explain the final stability and the Si/Al range in which each structure can be synthesized. The stabilization of intermediate species during the nucleation is proposed to orient the final result of the synthesis. A simple kinetic model is proposed to explain the synthesis process.
Formation of Thermally Robust Frustrated Lewis Pairs by Electrocyclic Ring Closure Reactions
Chen, Guo-Qiang,Kehr, Gerald,Daniliuc, Constantin G.,Mück-Lichtenfeld, Christian,Erker, Gerhard
, p. 5526 - 5530 (2016)
The phosphorus/boron-substituted hexatriene systems 6 undergo thermally induced electrocyclic ring closure to yield the cyclohexadiene-derived P/B frustrated Lewis pairs (FLPs) 7. Subsequent TEMPO oxidation gives the phenylene-bridged FLPs 8. Both systems activate dihydrogen and the thermally robust FLPs undergo carbon-carbon coupling reactions at a mesityl group upon treatment with dimethyl acetylenedicarboxylate at elevated temperatures.
Rh-PVP Catalyzed Reductive Amination of Phenols by Ammonia or Amines to Cyclohexylamines under Solvent-free Conditions
Chaudhari, Chandan,Nagaoka, Katsutoshi,Nishida, Yoshihide,Rumi, Saeki,Sato, Katsutoshi,Shiraishi, Masaya
supporting information, p. 81 - 84 (2022/01/12)
Colloidal metal nanoparticles were examined for reductive amination of phenol by ammonia under mild reaction conditions. The results showed that Rh-PVP was the most active catalyst for reductive amination reaction. Linear, cyclic, and amino alcohols were used as nucleophiles and converted to primary/secondary/tertiary amines. Using this strategy, the synthesis of an industrially important chemical, N-cyclohexyl- 2-pyrrolidone was explored.
Ni-Catalyzed reductive amination of phenols with ammonia or amines into cyclohexylamines
Cuypers, Thomas,Morias, Thomas,Windels, Simon,Marquez, Carlos,Van Goethem, Cédric,Vankelecom, Ivo,De Vos, Dirk E.
, p. 1884 - 1893 (2020/04/07)
Phenol and its derivatives, which naturally occur in lignocellulose, can be considered as a renewable feedstock not only for aromatic, but also for alicyclic compounds, such as primary and N-substituted cyclohexylamines. So far, the latter are mostly produced from non-renewable starting materials like benzene via problematic nitration/reduction or cross-coupling routes. Herein, an efficient reductive amination of phenol with ammonia or amines is demonstrated, for the first time without the need for rare and expensive noble metals and without using any additives. Various supported Ni catalysts were screened and we elucidated the influence of the key parameters, including the acid-base properties of the supporting material. Acquired knowledge was then applied to different phenol-ammonia/amine combinations, resulting in the synthesis of various primary, secondary and tertiary cyclohexylamines in fair to very high yields.
Electroactivated alkylation of amines with alcohols: Via both direct and indirect borrowing hydrogen mechanisms
Appiagyei, Benjamin,Bhatia, Souful,Keeney, Gabriela L.,Dolmetsch, Troy,Jackson, James E.
supporting information, p. 860 - 869 (2020/02/21)
A green, efficient N-alkylation of amines with simple alcohols has been achieved in aqueous solution via an electrochemical version of the so-called "borrowing hydrogen methodology". Catalyzed by Ru on activated carbon cloth (Ru/ACC), the reaction works well with methanol, and with primary and secondary alcohols. Alkylation can be accomplished by either of two different electrocatalytic processes: (1) in an undivided cell, alcohol (present in excess) is oxidized at the Ru/ACC anode; the aldehyde or ketone product condenses with the amine; and the resulting imine is reduced at an ACC cathode, combining with protons released by the oxidation. This process consumes stoichiometric quantities of current. (2) In a membrane-divided cell, the current-activated Ru/ACC cathode effects direct C-H activation of the alcohol; the resulting carbonyl species, either free or still surface-adsorbed, condenses with amine to form imine and is reduced as in (1). These alcohol activation processes can alkylate primary and secondary aliphatic amines, as well as ammonia itself at 25-70 °C and ambient pressure.
Ruthenium and Iron-Catalysed Decarboxylative N-alkylation of Cyclic Α-Amino Acids with Alcohols: Sustainable Routes to Pyrrolidine and Piperidine Derivatives
Afanasenko, Anastasiia,Hannah, Rachael,Yan, Tao,Elangovan, Saravanakumar,Barta, Katalin
, p. 3801 - 3807 (2019/07/31)
A modular and waste-free strategy for constructing N-substituted cyclic amines via decarboxylative N-alkylation of α-amino acids employing ruthenium- and iron-based catalysts is presented. The reported method allows the synthesis of a wide range of five- and six-membered N-alkylated heterocycles in moderate-to-excellent yields starting from predominantly proline and a broad range of benzyl alcohols, and primary and secondary aliphatic alcohols. Examples using pipecolic acid for the construction of piperidine derivatives, as well as the one-pot synthesis of α-amino nitriles, are also shown.
Unusual 1,1-Hydroboration Route to a Reactive Unsaturated Vicinal Frustrated Phosphane/Borane Lewis Pair
Ueno, Atsushi,Tao, Xin,Daniliuc, Constantin G.,Kehr, Gerald,Erker, Gerhard
supporting information, p. 2665 - 2668 (2018/09/10)
Piers' borane HB(C6F5)2 reacted with the alkyne Mes2P-C≡ ≡C-SiMe3 by a rarely observed 1,1-hydroboration reaction under kinetic control to give the unsaturated vicinal frustrated phosphane/borane Lewis pair 6, featuring both the PMes2 and SiMe3 groups at the same carbon atom C1. Compound 6 is a reactive P/B FLP which splits dihydrogen under mild conditions. Thermolysis at 100 °C converts it to the markedly less reactive P/B FLP regioisomer which bears the -SiMe3 substituent at carbon atom C2 adjacent to the B(C6F5)2 group. Most new compounds were characterized by X-ray diffraction.
Identification of Novel Bacterial Members of the Imine Reductase Enzyme Family that Perform Reductive Amination
France, Scott P.,Howard, Roger M.,Steflik, Jeremy,Weise, Nicholas J.,Mangas-Sanchez, Juan,Montgomery, Sarah L.,Crook, Robert,Kumar, Rajesh,Turner, Nicholas J.
, p. 510 - 514 (2018/01/27)
Reductive amination of carbonyl compounds constitutes one of the most efficient ways to rapidly construct chiral and achiral amine frameworks. Imine reductase (IRED) biocatalysts represent a versatile family of enzymes for amine synthesis through NADPH-mediated imine reduction. The reductive aminases (RedAms) are a subfamily of IREDs that were recently shown to catalyze imine formation as well as imine reduction. Herein, a diverse library of novel enzymes were expressed and screened as cell-free lysates for their ability to facilitate reductive amination to expand the known suite of biocatalysts for this transformation and to identify more enzymes with potential industrial applications. A range of ketones and amines were examined, and enzymes were identified that were capable of accepting benzylamine, pyrrolidine, ammonia, and aniline. Amine equivalents as low as 2.5 were employed to afford up to >99 % conversion, and for chiral products, up to >98 % ee could be achieved. Preparative-scale reactions were conducted with low amine equivalents (1.5 or 2.0) of methylamine, allylamine, and pyrrolidine, achieving up to >99 % conversion and 76 % yield.
Mild N-Alkylation of Amines with Alcohols Catalyzed by the Acetate Ru(OAc)2(CO)(DiPPF) Complex
Figliolia, Rosario,Baldino, Salvatore,Nedden, Hans G.,Zanotti-Gerosa, Antonio,Baratta, Walter
supporting information, p. 14416 - 14419 (2017/10/07)
The acetate complex Ru(OAc)2(DiPPF) (2) obtained from Ru(OAc)2(PPh3)2 (1) and 1,1′-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2(CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4-2 mol %) efficiently catalyzes the N-alkylation of primary and secondary alkyl and aromatic amines using primary alcohols ROH (R=Et, nPr, nBu, PhCH2) under mild reaction conditions (30–100 °C) with an alcohol/amine molar ratio of 10-100. Formation of the monohydride RuH(OAc)(CO)(DiPPF) (4) has been observed by reaction of 3 with iPrOH in the presence of NEt3 at RT through an equilibrium reaction.
