Kinetic Resolution and Dynamic Kinetic Resolution of Chromene by Rhodium‐Catalyzed Asymmetric Hydroarylation
作者:Qingjing Yang、Yanbo Wang、Shihui Luo、Jun (Joelle) Wang
DOI:10.1002/anie.201900721
日期:2019.4.8
A highly efficient kineticresolution and dynamickineticresolution of chromene is reported for the first time and they procced by a rhodium‐catalyzed asymmetric hydroarylation pathway. This new approach offers versatile access to various chiral 2,3‐diaryl‐chromanes containing vicinal stereogenic centers, as well as the recovered chiral flavenes, in high yields with excellent ee values (s factor up
In this work, an efficient palladiumcatalyzed annulation of 2-iodobiphenyl with a non-terminal alkene was developed. The key factor in this transformation was the formation of a highly reactive oxo-palladacycle intermediate, which was enabled by a neighboring hydroxyl group, and remarkably restrained the β-H elimination process. Mechanistically, control experiments demonstrated that the hydroxyl group
L-Proline is utilized as an efficient organocatalyst for the synthesis of substituted flavanones and chalcones in good yields. The efficiency of the catalyst was proved with a variety of substrates ranging from electron-deficient to electron-rich aryl aldehydes and 2-hydroxyacetophenones. (c) 2005 Elsevier Ltd. All rights reserved.
Synthesis of some new 1,3,5-trisubstituted pyrazolines bearing benzene sulfonamide as anticancer and anti-inflammatory agents
Thirteen new 2-pyrazoline derivatives bearing benzenesulfonamide moiety (2a-m) were synthesized by condensing appropriate chalcones with 4-hydrazinonbenzenesulfonamide hydrochloride and tested for anticancer and anti-inflammatory actions. According to the protocol of the National Cancer Institute (NCI) in vitro disease-oriented human cells screening panel assay compounds 2b, 2c, 2e, 2f and 2g exhibited considerable antitumor activities against the entire tested tumor cell lines and showed effective growth inhibition GI(50) (MG-MID) values of 2.63, 2.57, 6.61, 3.31 and 2.57 mu M, respectively, beside a cyclostatic activity TGI (MG-MID) 9.54, 8.51, 24.0, 19.9 and 8.71 mu M, respectively. Two compounds 2g and 2k showed more potent anti-inflammatory activity than celecoxib at 5 h in carrageenan-induced rat paw edema bioassay. These compounds (2g and 2k) proved to have superior gastrointestinal safety profiles as compared to celecoxib, when tested for their ulcerogenic effects. Compounds 2g and 2k showed no inhibition against the enzymatic activity of bovine COX-2 (in vitro). (C) 2011 Elsevier Ltd. All rights reserved.