Construction of Enantioenriched 9H-Fluorene Frameworks via a Cascade Reaction Involving Remote Vinylogous Dynamic
Cui-Xia Hu1, Lin Chen1, Di Hu1
1Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
Abstract:
The benzylic C-H group of α,α-dicyanoolefins from 3-substituted 1-indanones could be significantly activated via transmission along the aromatic system, thus enabling dynamic kinetic resolution via a traditional reversible deprotonation-protonation process. Enantioenriched 9-substituted 9H-fluorene frameworks were finally constructed through an asymmetric vinylogous Michael addition to nitroolefins, followed by a cascade cyclization and oxidative aromatization process, under the catalysis of a chiral bifunctional thiourea-tertiary amine.
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