An efficient and highly diastereoselective synthesis of carbocyclic spiropyrazolones via one-pot sequential dual organo-silver catalyzed Michael-hydroalkylation reactions
作者:Khyati Shukla、Sadhna Shah、Nirmal K. Rana、Vinod K. Singh
DOI:10.1016/j.tetlet.2018.11.064
日期:2019.1
An economical approach for the diastereoselective synthesis of highly functionalized carbocyclic spiropyrazolone derivatives having one quaternary and two tertiary stereocenters along with one exocyclic double bond exploiting dual organo-silver sequential catalysis has been developed. The unified method to both cyclohexyl and cyclopentyl spirocompounds involves the reaction of γ- and β-nitroalkynes
Enantioselective aminocatalytic synthesis of tetrahydropyrano[2,3-c]pyrazoles via a domino Michael-hemiacetalization reaction with alkylidene pyrazolones
作者:Rajendra Maity、Subhas Chandra Pan
DOI:10.1039/c7ob02170d
日期:——
An enantioselectiveorganocatalytic domino Michael-hemiacetalization reaction between alkylidene pyrazolones and cyclic ketones/pentanal has been revealed. The fused tetrahydropyranopyrazole products having three contiguous stereocentres were obtained with perfect diastereoselectivities and in moderate to good yields with good to high enantioselectivities. Also, few synthetic transformations of the
Bifunctional Squaramide-Catalyzed Asymmetric [3 + 2] Cyclization of 2-(1-Methyl-2-oxoindolin-3-yl)malononitriles with Unsaturated Pyrazolones To Construct Spirooxindole-Fused Spiropyrazolones
作者:Ye Lin、Bo-Liang Zhao、Da-Ming Du
DOI:10.1021/acs.joc.9b01268
日期:2019.8.16
The present paper reports a highlystereoselectivesynthesis of spirooxindole-fused spiropyrazolones through the asymmetric [3 + 2] cyclization reaction of 2-(1-methyl-2-oxoindolin-3-yl)malononitriles with unsaturated pyrazolones under mild conditions. With only a 1 mol % bifunctional squaramide catalyst, a series of chiral dispirocyclic pyrazolone derivatives were attained in high yields (85–97%)
Construction of Spirocyclopropane-Linked Heterocycles Containing Both Pyrazolones and Oxindoles through Michael/Alkylation Cascade Reactions
作者:Jun-Hua Li、Ting-Fan Feng、Da-Ming Du
DOI:10.1021/acs.joc.5b01940
日期:2015.11.20
diastereoselective Michael/alkylation cascade reaction of arylidenepyrazolones with 3-chlorooxindoles catalyzed by DIPEA was developed. A variety of highly functionalized spiro-pyrazolone-cyclopropane-oxindoles were obtained in excellent yields (up to 99%) with good to excellent diastereoselectivities (up to >25:1 dr). Moreover, the squaramide-catalyzed asymmetric reactions of arylidenepyrazolones with
Quinine-catalyzed asymmetric domino Michael-cyclization reaction for the synthesis of spirocyclic oxindoles bearing two spiro quaternary centers and three consecutive stereocenters
An efficient organocatalytic diastereo- and enantioselective method for the construction of spirocyclic oxindole derivatives bearing twospiroquaternarycenters and three consecutive stereocenters via a domino Michael/cyclization process has been developed. Using commercially available quinine as catalyst, the reactions of 3-isothiocyanato oxindoles with unsaturated pyrazolones and unsaturated isoxazolones