608128-34-3Relevant academic research and scientific papers
Asymmetric Catalytic Formal 1,4-Allylation of β,γ-Unsaturated α-Ketoesters: Allylboration/Oxy-Cope Rearrangement
Tang, Qiong,Fu, Kai,Ruan, Peiran,Dong, Shunxi,Su, Zhishan,Liu, Xiaohua,Feng, Xiaoming
, p. 11846 - 11851 (2019/07/19)
A highly enantioselective formal conjugate allyl addition of allylboronic acids to β,γ-unsaturated α-ketoesters has been realized by employing a chiral NiII/N,N′-dioxide complex as the catalyst. This transformation proceeds by an allylboration/oxy-Cope rearrangement sequence, providing a facile and rapid route to γ-allyl-α-ketoesters with moderate to good yields (65–92 %) and excellent ee values (90–99 % ee). The isolation of 1,2-allylboration products provided insight into the mechanism of the subsequent oxy-Cope rearrangement reaction: substrate-induced chiral transfer and a chiral Lewis acid accelerated process. Based on the experimental investigations and DFT calculations, a rare boatlike transition-state model is proposed as the origin of high chirality transfer during the oxy-Cope rearrangement.
Facile synthesis of substituted diaryl sulfones: Via a [3 + 3] benzannulation strategy
Tang, Xiang-Zheng,Tong, Lang,Liang, Hua-Ju,Liang, Jie,Zou, Yong,Zhang, Xue-Jing,Yan, Ming,Chan, Albert S. C.
, p. 3560 - 3563 (2018/05/26)
A base-mediated [3 + 3] benzannulation strategy for the conversion of 1,3-bis(sulfonyl)propenes and β,γ-unsaturated α-ketoesters to diaryl sulfones has been developed. This method provides facile, metal-free and efficient access to highly substituted diaryl sulfones in good to excellent yields. In addition, the sulfonyl group could be easily removed or converted to other functional groups via an organostannane intermediate.
Enantioselective NHC-catalysed redox [4+2]-hetero-Diels-Alder reactions using α-aroyloxyaldehydes and unsaturated ketoesters
Taylor, James E.,Davies, Alyn T.,Douglas, James J.,Churchill, Gwydion,Smith, Andrew D.
, p. 355 - 366 (2017/02/15)
N-Heterocyclic carbene (NHC)-catalysed redox [4+2]-hetero-Diels-Alder reactions of α-aroyloxyaldehydes with either β,γ-unsaturated α-ketoesters or α,β-unsaturated γ-ketoesters generates substituted syn-dihydropyranones in good yield with excellent enantioselectivity (up to >99:1 er). The product diastereoselectivity is markedly dependent upon the nature of the unsaturated enone substituent. The presence of either electron-neutral or electron-rich aryl substituents gives excellent diastereoselectivity (up to >99:5 dr), while electron-deficient aryl substituents give reduced diastereoselectivity. In these cases, the syn-dihydropyranone products are more susceptible to base-promoted epimerisation at the C(4)-position under the reaction conditions, accounting for the lower diastereoselectivity obtained.
Boosting Chemical Stability, Catalytic Activity, and Enantioselectivity of Metal-Organic Frameworks for Batch and Flow Reactions
Chen, Xu,Jiang, Hong,Hou, Bang,Gong, Wei,Liu, Yan,Cui, Yong
, p. 13476 - 13482 (2017/10/05)
A key challenge in heterogeneous catalysis is the design and synthesis of heterogeneous catalysts featuring high catalytic activity, selectivity, and recyclability. Here we demonstrate that high-performance heterogeneous asymmetric catalysts can be engineered from a metal-organic framework (MOF) platform by using a ligand design strategy. Three porous chiral MOFs with the framework formula [Mn2L(H2O)2] are prepared from enantiopure phosphono-carboxylate ligands of 1,1′-biphenol that are functionalized with 3,5-bis(trifluoromethyl)-, bismethyl-, and bisfluoro-phenyl substituents at the 3,3′-position. For the first time, we show that not only chemical stability but also catalytic activity and stereoselectivity of the MOFs can be tuned by modifying the ligand structures. Particularly, the MOF incorporated with -CF3 groups on the pore walls exhibits enhanced tolerance to water, weak acid, and base compared with the MOFs with -F and -Me groups. Under both batch and flow reaction systems, the CF3-containing MOF demonstrated excellent reactivity, selectivity, and recyclability, affording high yields and enantioselectivities for alkylations of indoles and pyrrole with a range of ketoesters or nitroalkenes. In contrast, the corresponding homogeneous catalysts gave low enantioselectivity in catalyzing the tested reactions.
SUBSTITUTED PYRAZOLO[3,4-b]PYRIDIN-6-CARBOXYLIC ACIDS AND METHOD OF USE
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, (2017/05/14)
The present invention provides for compounds of formula (I) wherein R1, R2, R3, and R4 have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions mediated and modulated by CFTR, including cystic fibrosis, Sj?gren's syndrome, pancreatic insufficiency, chronic obstructive lung disease, and chronic obstructive airway disease. Also provided are pharmaceutical compositions comprised of one or more compounds of formula (I).
A New Strategy for Enantioselective Construction of Multisubstituted Five-Membered Oxygen Heterocycles via a Domino Michael/Hemiketalization Reaction
Hua, Yuan-Zhao,Liu, Meng-Meng,Huang, Pei-Jin,Song, Xixi,Wang, Min-Can,Chang, Jun-Biao
, p. 11994 - 11998 (2015/08/18)
A new highly enantioselective domino Michael/hemiketalization reaction of α-hydroxyacetophenone with β,γ-unsaturated α-keto esters for the synthesis of 2,2,4,5-tetrasubstituted chiral tetrahydrofurans is reported. With 2 mol% intramolecular dinuclear zinc
4,5-DIHYDRO-1H-PYRAZOLE DERIVATIVE OR SALTS THEREOF, AND PHARMACEUTICAL COMPOSITION COMPRISING SAME
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, (2015/11/16)
The present invention provides a 4,5-dihydro-1H-pyrazole derivative or its pharmaceutically acceptable salt, a process for the preparation thereof, and a pharmaceutical composition comprising the same. The 4,5-dihydro-1H-pyrazole derivative or its pharmaceutically acceptable salt effectively increases the LXR transcriptional activity, and therefore can be usefully applied for preventing or treating a dysfunction in cholesterol metabolism, such as cholesterol gallstone, hyperlipidemia, or coronary atherosclerosis.
Synthesis of functionalized 2,5-dihydro-1,2-oxaphospholes via one-pot three-component reaction
Balalaie, Saeed,Baoosi, Leila,Tahoori, Fatemeh,Rominger, Frank,Bijanzadeh, Hamid Reza
, p. 101 - 105 (2015/01/30)
An efficient one-pot synthesis of novel 2,5-dihydro-1,2-oxaphosphole derivatives via a three-component reaction of triphenyl phosphine, dialkyl acetylenedicarboxylates, and methyl (arylmethylidene) pyruvates has been reported. Carrying out the reaction in
Phosphine-catalyzed domino reactions: A route to functionalized bicyclic skeletons
Li, Erqing,Huang, You
supporting information, p. 3520 - 3527 (2014/04/03)
A novel strategy that involves phosphine-catalyzed sequential [2+3] and [3+2] annulation reactions was developed. In this domino reaction, γ-substituted allenoates were used as novel C4 synthons, and the bicyclic cyclopenta[b]dihydrofuran derivatives were produced in good to excellent diastereoselectivities and yields under mild conditions. Furthermore, preliminary studies on an asymmetric variant of this reaction proceeded with moderate enantioselectivity.
Organocatalytic Functionalization of carboxylic acids: Isothiourea- catalyzed asymmetric intra- and intermolecular Michael addition-lactonizations
Belmessieri, Dorine,Morrill, Louis C.,Simal, Carmen,Slawin, Alexandra M. Z.,Smith, Andrew D.
, p. 2714 - 2720 (2011/04/23)
Tetramisole promotes the catalytic asymmetric intramolecular Michael addition-lactonization of a variety of enone acids, giving carbo- and heterocyclic products with high diastereo- and enantiocontrol (up to 99:1 dr, up to 99% ee) that are readily derivatized to afford functionalized indene and dihydrobenzofuran carboxylates. Chiral isothioureas also promote the catalytic asymmetric intermolecular Michael addition-lactonization of arylacetic acids and α-keto-β,γ-unsaturated esters, giving anti-dihydropyranones with high diastereo- and enantiocontrol (up to 98:2 dr, up to 99% ee).
