13268-54-7Relevant academic research and scientific papers
Access to benzo-fused nine-membered heterocyclic alkenes with a trifluoromethyl carbinol moiety: Via a double decarboxylative formal ring-expansion process under palladium catalysis
Das, Pulakesh,Gondo, Satoshi,Nagender, Punna,Uno, Hiroto,Tokunaga, Etsuko,Shibata, Norio
, p. 3276 - 3281 (2018)
Direct access to pharmaceutically attractive benzo-fused nine-membered heterocyclic alkenes 3 with a trifluoromethyl carbinol moiety was achieved via a palladium-catalyzed double-decarboxylative formal ring-expansion process from six-membered trifluoromethyl benzo[d][1,3]oxazinones 1 to nine-membered trifluoromethyl benzo[c][1,5]oxazonines 3 in the presence of vinylethylene carbonates 2. Generation of a Pd-π-allyl zwitterionic intermediate was proposed in the catalytic cycle. The trifluoromethyl group in the benzoxazinanones 1 plays an important role throughout the transformation. Diastereoselective chemical transformations of products 3 were also demonstrated.
Catalyst Control in Switching the Site Selectivity of C?H Olefinations of 1,2-Dihydroquinolines: An Approach to Positional-Selective Functionalization of Quinolines
Das, Riki,Khot, Nandkishor Prakash,Deshpande, Akanksha Santosh,Kapur, Manmohan
, p. 927 - 938 (2020)
A unique approach to achieve site-selective C?H olefinations exclusively at the C-3- or C-8-positions in the quinoline framework has been developed by catalyst control. Distal C(3)?H functionalization is achieved by using palladium catalysis, whereas proximal C(8)?H functionalization is obtained by employing ruthenium catalysis. Switching the site selectivity within a single substrate directly indicates two diverse pathways, which are operating under the palladium- and ruthenium-catalyzed reaction conditions.
Hydrogen Bonding Networks Enable Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis**
Anh To, Tuong,Pei, Chao,Koenigs, Rene M.,Vinh Nguyen, Thanh
, (2022/02/17)
Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen-bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl-olefin metathesis reactions by hydrogen-bonding-assisted Br?nsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para-toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Br?nsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.
Diverting β-Hydride Elimination of a ?-Allyl PdIICarbene Complex for the Assembly of Disubstituted Indolines via a Highly Diastereoselective (4 + 1)-Cycloaddition
Tucker, Zachary D.,Hill, Harrison M.,Smith, Andrew L.,Ashfeld, Brandon L.
supporting information, p. 6605 - 6609 (2020/09/02)
A Pd0-catalyzed formal (4 + 1)-cycloaddition approach to 2,3-disubstituted dihydroindoles is described. The diastereoselective formation of dihydroindoles that is highlighted by a carbene migratory insertion/reductive elimination sequence proceeding via a ?-allyl PdII-species compliments existing methods of indoline assembly.
Enantioselective Synthesis of 4-Cyanotetrahydroquinolines via Ni-Catalyzed Hydrocyanation of 1,2-Dihydroquinolines
Fang, Xianjie,Gao, Jihui,Jiao, Mingdong
, (2020/11/18)
A Ni-catalyzed asymmetric hydrocyanation that enables the formation of 4-cyanotetrahydroquinolines in good yields with excellent enantioselectivities is presented herein. A variety of functional groups are well-tolerated, and a gram-scale reaction supports the synthetic potential of the transformation. Additionally, several crucial intermediates for pharmaceutically active agents, including a PGD2 receptor antagonist, are now accessible through asymmetric synthesis using this new protocol.
Synthesis of 1,2-Dihydroquinolines via Hydrazine-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis
Zhang, Yunfei,Sim, Jae Hun,Macmillan, Samantha N.,Lambert, Tristan H.
supporting information, p. 6026 - 6030 (2020/08/05)
The synthesis of 1,2-dihydroquinolines by the hydrazine-catalyzed ring-closing carbonyl-olefin metathesis (RCCOM) of N-prenylated 2-aminobenzaldehydes is reported. Substrates with a variety of substitution patterns are shown. With an acid-labile protecting group on the nitrogen atom, in situ deprotection and autoxidation furnish quinoline. In comparison with related oxygen-containing substrates, the cycloaddition step of the catalytic cycle is shown to be slower, but the cycloreversion is found to be more facile.
Enantioselective Synthesis of 4-Aminotetrahydroquinolines via 1,2-Reductive Dearomatization of Quinolines and Copper(I) Hydride-Catalyzed Asymmetric Hydroamination
Xu-Xu, Qing-Feng,Zhang, Xiao,You, Shu-Li
supporting information, p. 5357 - 5362 (2019/09/06)
A 1,2-reductive dearomatization of quinolines and copper(II) acetate monohydrate/(R,R)-Ph-BPE/P(p-tolyl)3-catalyzed enantioselective hydroamination sequence was developed, affording diverse 4-amino-1,2,3,4-tetrahydroquinolines with high levels of enantioselectivity in either a stepwise or one-pot fashion. Pleasingly, internal cis-cyclic alkenes, which are challenging substrates in copper hydride-catalyzed enantioselective hydroamination reactions, were transformed efficiently under mild conditions.
Heteroatom-guided, palladium-catalyzed regioselective C-H functionalization in the synthesis of 3-arylquinolines
Tiwari, Virendra Kumar,Pawar, Govind Goroba,Das, Riki,Adhikary, Amit,Kapur, Manmohan
, p. 3310 - 3313 (2013/07/26)
A new approach for the regioselective functionalization of the C-3-position of quinolines is described. The method utilizes heteroatom guided regioselective C-3 palladation followed by arylation via transmetalation with aryl boronic acids to yield 3-aryl-N-acyl-1,2-dihydroquinolines. In a one-pot sequence, N-deacylation followed by aromatization leads to important 3-arylquinolines in good yields.
The Au(I)-catalyzed intramolecular hydroarylation of terminal alkynes under mild conditions: Application to the synthesis of 2H-chromenes, coumarins, benzofurans, and dihydroquinolines
Menon, Rajeev S.,Findlay, Alison D.,Bissember, Alex C.,Banwell, Martin G.
supporting information; experimental part, p. 8901 - 8903 (2010/03/01)
(Chemical Equation Presented) Operationally simple Au(I)-catalyzed intramolecular hydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily accessible starting materials.
Decarboxylative cyclizations and cycloadditions of palladium-polarized aza-ortho-xylylenes
Wang, Chao,Pahadi, Nirmal,Tunge, Jon A.
experimental part, p. 5102 - 5109 (2009/12/01)
Vinyl benzoxazinones undergo decarboxylation in the presence of palladium catalysts to form palladium-polarized aza-ortho-xylylenes, which are versatile reaction intermediates. These palladium-polarized aza-ortho-xylylenes are generated under exceptionall
