83926-73-2Relevant articles and documents
An Iron-Mesoionic Carbene Complex for Catalytic Intramolecular C-H Amination Utilizing Organic Azides
Albrecht, Martin,Keilwerth, Martin,Meyer, Karsten,Pividori, Daniel M.,Stroek, Wowa
, p. 20157 - 20165 (2021/12/09)
The synthesis of N-heterocycles is of paramount importance for the pharmaceutical industry. They are often synthesized through atom economic and environmentally unfriendly methods, generating significant waste. A less explored, but greener, alternative is
Efficient C-H Amination Catalysis Using Nickel-Dipyrrin Complexes
Betley, Theodore A.,Clarke, Ryan M.,Dong, Yuyang,Porter, Gerard J.
, p. 10996 - 11005 (2020/07/08)
A dipyrrin-supported nickel catalyst (AdFL)Ni(py) (AdFL: 1,9-di(1-adamantyl)-5-perfluorophenyldipyrrin; py: pyridine) displays productive intramolecular C-H bond amination to afford N-heterocyclic products using aliphatic azide substrates. The catalytic amination conditions are mild, requiring 0.1-2 mol% catalyst loading and operational at room temperature. The scope of C-H bond substrates was explored and benzylic, tertiary, secondary, and primary C-H bonds are successfully aminated. The amination chemoselectivity was examined using substrates featuring multiple activatable C-H bonds. Uniformly, the catalyst showcases high chemoselectivity favoring C-H bonds with lower bond dissociation energy as well as a wide range of functional group tolerance (e.g., ethers, halides, thioetheres, esters, etc.). Sequential cyclization of substrates with ester groups could be achieved, providing facile preparation of an indolizidine framework commonly found in a variety of alkaloids. The amination cyclization reaction mechanism was examined employing nuclear magnetic resonance (NMR) spectroscopy to determine the reaction kinetic profile. A large, primary intermolecular kinetic isotope effect (KIE = 31.9 ± 1.0) suggests H-atom abstraction (HAA) is the rate-determining step, indicative of H-atom tunneling being operative. The reaction rate has first order dependence in the catalyst and zeroth order in substrate, consistent with the resting state of the catalyst as the corresponding nickel iminyl radical. The presence of the nickel iminyl was determined by multinuclear NMR spectroscopy observed during catalysis. The activation parameters (ΔH? = 13.4 ± 0.5 kcal/mol; ΔS?= -24.3 ± 1.7 cal/mol·K) were measured using Eyring analysis, implying a highly ordered transition state during the HAA step. The proposed mechanism of rapid iminyl formation, rate-determining HAA, and subsequent radical recombination was corroborated by intramolecular isotope labeling experiments and theoretical calculations.
PROCESS FOR PREPARING 4-CYCLOHEXYL-2-METHYL-2-BUTANOL
-
Paragraph 0121-0123; 0136-0137, (2015/09/22)
The present invention relates to a process for preparing 4-cyclohexyl-2-methyl-2-butanol. The process comprises the following steps: a) reaction of styrene with isopropanol at elevated temperature to obtain 4-phenyl-2-methyl-2-butanol, andb) heterogeneously catalyzed hydrogenation of 4-phenyl-2-methyl-2-butanol over a catalyst suitable for ring hydrogenation of aromatics.
PROCESS FOR PRODUCING 4-CYCLOHEXYL-2-METHYL-2-BUTANOL
-
, (2014/01/17)
The present invention relates to the field of perfumery. More particularly, it concerns a process for the preparation of 2-methyl-4-phenyl-2-butanol, or even 4-cyclohexyl-2-methyl-2-butanol from 4,4-dimethyl-2,6-diphenyl-1,3-dioxane.
PROCESS FOR PREPARING 4-CYCLOHEXYL-2-METHYL-2-BUTANOL
-
Paragraph 0108-0109, (2013/03/28)
A process for preparing 4-cyclohexyl-2-methyl-2-butanol, comprising: a) reaction of styrene with isopropanol at elevated temperature to obtain 2-methyl-4-phenyl-2-butanol, andb) heterogeneously catalyzed hydrogenation of 2-methyl-4-phenyl-2-butanol over a catalyst suitable for ring hydrogenation of aromatics, where the molar ratio of the styrene used in step a) to the isopropanol used in step a) is in the range from 1:below 5 to 1:0.5.
