Bifunctional Squaramide-Catalyzed Asymmetric [3 + 2] Cyclization of 2‑(1-Methyl-2-oxoindolin-3-yl)malononitriles with Unsaturated Pyrazolones To Construct Spirooxindole-Fused Spiropyrazolones

The present paper reports a highly stereoselective synthesis 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 ca...

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Bibliographic Details
Published inJournal of organic chemistry Vol. 84; no. 16; pp. 10209 - 10220
Main Authors Lin, Ye, Zhao, Bo-Liang, Du, Da-Ming
Format Journal Article
LanguageEnglish
Published WASHINGTON American Chemical Society 16.08.2019
Amer Chemical Soc
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
BISPIROOXINDOLES
HETEROCYCLES
ENANTIOSELECTIVE CONSTRUCTION
DERIVATIVES
ACCESS
SPIROCYCLOPENTANE OXINDOLES
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Summary:The present paper reports a highly stereoselective synthesis 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%) with excellent stereoselectivities (up to >99% ee and in all cases >20:1 dr). Moreover, gram-scale synthesis and further transformation of the products were also demonstrated.
Bibliography:ObjectType-Article-1
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content type line 23
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.9b01268