Synthesis 2018; 50(21): 4243-4253
DOI: 10.1055/s-0036-1591592
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© Georg Thieme Verlag Stuttgart · New York

Asymmetric Cycloetherification by Bifunctional Organocatalyst

Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku-Katsura, Nishkyo, 615-8510 Kyoto, Japan   Email: matsubara.seijiro.2@kyoto-u.ac.jp
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Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku-Katsura, Nishkyo, 615-8510 Kyoto, Japan   Email: matsubara.seijiro.2@kyoto-u.ac.jp
› Author Affiliations
This work was supported financially by JSPS KAKENHI Grant Number 15H05845, 16K13994, 17K19120, 18K14214, and 18H04258.
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Publication History

Received: 17 April 2018

Accepted: 27 April 2018

Publication Date:
26 June 2018 (online)


Published as part of the Special Section on the 26th French–Japanese Symposium on Medicinal and Fine Chemistry

Abstract

Attempts to obtain enantiomerically enriched tetrahydrofuran derivatives via an intramolecular oxy-Michael addition reaction of ε-hydroxyenone is discussed. Despite previous difficulties associated with the asymmetric induction of this reaction, which can proceed even without a catalyst, a highly efficient asymmetric induction was realized using a bifunctional organocatalyst derived from a cinchona alkaloid. The reaction could be extended to ζ-hydroxyenone to yield an optically active tetrahydropyran derivative with a high ee. In these reactions, it is important for the gentle acidic and basic sites in the bifunctional organocatalyst to be arranged properly within the molecular skeleton of the catalyst. The high performance asymmetric induction relied on the affinity of the catalyst for the substrate, which played an important role. A disubstituted tetrahydropyran synthesis could be effectively performed via kinetic resolution using ζ-hydroxyenone containing a secondary alcohol moiety using a chiral phosphoric acid catalyst.

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