Squaramide-catalyzed asymmetric Mannich reactions between 3-fluorooxindoles and pyrazolinone ketimines

An enantioselective Mannich reaction between 3-fluorooxindoles and pyrazolinone ketimines has been developed for the construction of amino-pyrazolone-oxindoles containing stereogenic C-F units. Based on this new protocol that allows for the generation of two adjacent tetrasubstituted stereocenters,...

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Published inOrganic & biomolecular chemistry Vol. 17; no. 3; pp. 7182 - 7191
Main Authors Zhang, Qing-Da, Zhao, Bo-Liang, Li, Bing-Yu, Du, Da-Ming
Format Journal Article
LanguageEnglish
Published CAMBRIDGE Royal Soc Chemistry 14.08.2019
Royal Society of Chemistry
Subjects
Chemical reactions
Chemistry
Chemistry, Organic
Crystallography
Enantiomers
Fluorination
Imines
Physical Sciences
Science & Technology
PYRAZOLIN-5-ONES
CONSTRUCTION
PYRAZOLONES
CHIRAL SQUARAMIDE
INHIBITORS
DERIVATIVES
MICHAEL ADDITION
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Summary:An enantioselective Mannich reaction between 3-fluorooxindoles and pyrazolinone ketimines has been developed for the construction of amino-pyrazolone-oxindoles containing stereogenic C-F units. Based on this new protocol that allows for the generation of two adjacent tetrasubstituted stereocenters, a variety of structurally diverse fluorinated amino-pyrazolone-oxindoles were obtained in good to excellent yields with excellent diastereoselectivities and enantioselectivities (up to 98% yield, >20 : 1 dr and >99% ee). What's more, good yield and high stereoselectivities were obtained in the gram-scale reaction. Squaramide-catalyzed asymmetric Mannich reaction between 3-fluorooxindoles and pyrazolinone ketimines afforded fluorinated amino-pyrazolone-oxindoles with two quaternary stereocenters in good to excellent yields with excellent stereoselectivities.
Bibliography:Electronic supplementary information (ESI) available. CCDC
For ESI and crystallographic data in CIF or other electronic format see DOI
10.1039/c9ob01350d
1912247
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ISSN:1477-0520
1477-0539
1477-0539
DOI:10.1039/c9ob01350d