Asymmetric Transfer Hydrogenation of 2,3-Disubstituted Flavanones through Dynamic Kinetic Resolution Enabled by RetroOxa-Michael Addition: Construction of Three Contiguous Stereogenic Centers

A ruthenium-catalyzed asymmetric transfer hydrogenation of 2,3-disubstituted flavanones was developed for the construction of three contiguous stereocenters under basic conditions through a combination of dynamic kinetic resolution and retro-oxa-Michael addition, giving chiral flavanols with excelle...

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Bibliographic Details
Published inJournal of organic chemistry Vol. 87; no. 11; pp. 7521 - 7530
Main Authors Xie, Qing-Xian, Liu, Li-Xia, Zhu, Zhou-Hao, Yu, Chang-Bin, Zhou, Yong-Gui
Format Journal Article
LanguageEnglish
Published WASHINGTON Amer Chemical Soc 03.06.2022
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
GLYCOSIDES
PHTHALIDES
CHROMANONES
ALLYLIC ALKYLATION
ELIMINATION
RACEMIZATION
INHIBITOR
ENANTIOSELECTIVE TOTAL-SYNTHESIS
DERIVATIVES
ACCESS
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ISSN0022-3263
1520-6904
DOI10.1021/acs.joc.2c00418

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Summary:A ruthenium-catalyzed asymmetric transfer hydrogenation of 2,3-disubstituted flavanones was developed for the construction of three contiguous stereocenters under basic conditions through a combination of dynamic kinetic resolution and retro-oxa-Michael addition, giving chiral flavanols with excellent enantioselectivities and diastereoselectivities. The reaction proceeded via a base-catalyzed retro-oxa-Michael addition to racemize two stereogenic centers simultaneously in concert with a highly enantioselective ketone transfer hydrogenation step. The asymmetric transfer hydrogenation could be achieved at gram scale without loss of the activity and enantioselectivity.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.2c00418