Chiral Spirobipyridine Synthesis by Cobalt-Catalyzed Enantioselective Double [2 + 2 + 2] Cycloaddition
Ke Li1, Danyang Zhu1, Luyu Cao1
1Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
None:
Chiral spirobiindanes are recognized as the privileged structures in the field of asymmetric catalysis. However, the structurally similar chiral spirobipyridines have not yet been explored as chiral ligands or organocatalysts due to the absence of efficient synthetic methods. Herein, we report a cobalt-catalyzed enantioselective synthesis of spirobipyridines via double [2 + 2 + 2] cycloaddition reaction. Spirobipyridines with ortho- or meta-substituents could be obtained with exclusive regioselectivity and up to 99% ee in the presence of cobalt and bisoxazolinephosphine ligands. Spirobipyridines coordinate with transition metals as chiral ligands. Spirobipyridine dioxides can be applied as chiral organocatalysts in the asymmetric allylation of aldehydes.
Related Concept Videos
Cycloaddition Reactions: Overview
Prochirality
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Cycloaddition Reactions: MO Requirements for Thermal Activation


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)