Enantioselective N‐Heterocyclic Carbene Catalyzed Cyclopentene Synthesis via the β‐Azolium Ylide

Herein we report the cycloisomerization of electron‐poor 1,5‐dienes via the β‐azolium ylide to give enantioenriched cyclopentenes. The reaction is mediated by a chiral N‐heterocyclic carbene (NHC) catalyst, exploits readily available substrates, has good generality (17 examples), and displays excell...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2018-08, Vol.57 (32), p.10299-10303
Main Authors: Scott, Lydia, Nakano, Yuji, Zhang, Changhe, Lupton, David W.
Format: Article
Language:English
Subjects:
1,4-addition
Chemical synthesis
Cyclopentene
Dienes
Enantiomers
Isomerization
N-heterocyclic carbenes
organocatalysis
Substrates
Tethers
Viability
β-azolium ylide
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Summary:Herein we report the cycloisomerization of electron‐poor 1,5‐dienes via the β‐azolium ylide to give enantioenriched cyclopentenes. The reaction is mediated by a chiral N‐heterocyclic carbene (NHC) catalyst, exploits readily available substrates, has good generality (17 examples), and displays excellent enantioselectivity (mostly >94:6). Studies demonstrating the viability of a related dynamic kinetic resolution are reported, as are those with alternate tethers and derivatizations. High five! A highly enantioselective synthesis of cyclopentenes through cycloisomerization of electron poor 1,5‐dienes was developed. The reaction is mediated by a chiral NHC catalyst, providing 17 cyclopentenes in good yields and with high enantiopurity. The reaction proceeds via the β‐azolium ylide, thus providing a relatively rare example of a conjugate‐acceptor umpolung.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201804271