Chiral Squaramide-Catalyzed Michael/Alkylation Cascade Reaction for the Asymmetric Synthesis of Nitro-Spirocyclopropanes
作者:Bo-Liang Zhao、Da-Ming Du
DOI:10.1002/ejoc.201500533
日期:2015.8
diastereoselective and enantioselective cyclopropanation reaction has been developed by employing a Michael/alkylationcascadereaction between (E)-3-arylenechroman-4-one or (E)-2-arylideneindan-1-one derivatives and a bromonitroalkane with a chiral squaramide catalyst. This reaction constitutes a facile asymmetricsynthesis for nitro-spirocyclopropanes that have three adjacent stereogenic centers, including
Facile synthesis of spiro chromanone-tetrahydrothiophenes with three contiguous stereocenters via sulfa-Michael/aldol cascade reactions
作者:Ya-Jian Hu、Xiao-Bing Wang、Su-Yi Li、Sai-Sai Xie、Kelvin D.G. Wang、Ling-Yi Kong
DOI:10.1016/j.tetlet.2014.11.026
日期:2015.1
A novel sulfa-Michael/aldol cascade reaction of (E)-3-arylidenechroman-4-ones with 1,4-dithiane-2,5-diol has been developed. This method provides a new practical and facile approach to 4′-hydroxy-2′-aryl-4′,5′-dihydro-2′H-spiro[chroman-3,3′-thiophen]-4-ones with three contiguous stereocenters in high yields. The transformation is atom-economic with good to excellent diastereoselectivities.
Intermolecular Reductive Cyclodimerization of Cyclic α,β-Unsaturated Ketones Promoted by a Low-Valent Titanium Reagent: A Facile Synthesis of Some New Spiro Compounds
作者:Da-Qing Shi、Guo-Lan Dou、Zheng-Yi Li、Chun-Ling Shi、Xiao-Yue Li、Hong Jiang、Sai-Nan Ni、Shun-Jun Ji
DOI:10.1055/s-2007-983707
日期:2007.6
β-unsaturated ketones such as 2-benzylideneindan-1-ones, 2-benzylidene-1 -tetralones, 3-benzylidenechroman-4-ones, and 3-benzylidenethiochroman-4-ones induced by a low-valent titanium reagent were studied. Some new spiro compounds were prepared in good yields under neutral and mild conditions. High stereoselectivity was achieved and the stereochemistry of the products was confirmed by X-ray diffraction
α,β-不饱和酮如 2-benzylideneindan-1-ones、2-benzylidene-1-tetralones、3-benzylidenechroman-4-ones 和 3-benzylidenethiochroman-4-ones 的分子间还原环二聚反应对低价钛试剂进行了研究。一些新的螺环化合物在中性和温和条件下以高收率制备。实现了高立体选择性,并通过 X 射线衍射分析证实了产物的立体化学。
Synthesis and Biological Evaluation of 3-Benzylidene-4-chromanone Derivatives as Free Radical Scavengers and α-Glucosidase Inhibitors
A series of 3-benzylidene-4-chromanone derivatives (3–20) were synthesized and the structure–activity relationships for antioxidant and α-glucosidase inhibitory activities were evaluated. Among synthesized compounds, compounds 5, 13, 18, which contain catechol moiety, showed the potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (5: EC50 13 µM; 13: EC50 14 µM; 18: EC50 13 µM). The compounds 12, 14, 18 showed higher α-glucosidase inhibitory activity (12: IC50 15 µM; 14: IC50 25 µM; 18: IC50 28 µM). The compound 18 showed both of potent DPPH radical scavenging and α-glucosidase inhibitory activities. These data suggest that 3-benzylidene-4-chromanone derivatives, such as compound 18, may serve as the lead compound for the development of novel α-glucosidase inhibitors with antioxidant activity.
Asymmetric Three-Component Cyclizations toward Structurally Spiro Pyrrolidines via Bifunctional Phosphonium Salt Catalysis
作者:Lixiang Zhu、Xiaoyu Ren、Zhongxiu Liao、Jianke Pan、Chunhui Jiang、Tianli Wang
DOI:10.1021/acs.orglett.9b03282
日期:2019.11.1
Asymmetric multicomponent reactions toward optically pure compounds are highly attractive but extremely challenging. Presented herein is a highly diastereo- and enantioselectivethree-component cyclization of exocyclic alkenes with aldehydes and amino esters, which was enabled by bifunctional phosphonium salt catalysts. A wide range of multiply substituted spiro pyrrolidine derivatives were prepared