Regio‐ and Chemoselective Formal (4+1) Carbocyclization of Chalcones with Internal Alkynes via Rhodium(III) Catalysis

A rhodium(III)‐catalyzed oxidative cyclization of chalcones with internal alkynes is reported, generating biologically important 3,3‐disubstituted 1‐indanones along with reusable aromatic aldehydes. This transformation features unique (4+1) reaction mode, excellent regioselectivity in alkyne inserti...

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Published in:Angewandte Chemie International Edition 2023-07, Vol.62 (30), p.e202305983-n/a
Main Authors: Song, Shuaishuai, Lai, Yunfei, Tuo, Zekun, Zhong, Jianming, Zhou, Wang
Format: Article
Language:English
Subjects:
Aldehydes
Alkyne
Alkynes
Annulation
Carbocyclization
Catalysis
Chalcone
Chemical reactions
Regioselectivity
Rhodium
Rhodium Catalysis
Steric hindrance
Substrates
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Summary:A rhodium(III)‐catalyzed oxidative cyclization of chalcones with internal alkynes is reported, generating biologically important 3,3‐disubstituted 1‐indanones along with reusable aromatic aldehydes. This transformation features unique (4+1) reaction mode, excellent regioselectivity in alkyne insertion, broad substrate scope, allows for the construction of quaternary carbon centers, and is scalable. Steric hindrance from substrate and ligand probably controls the chemoselectivity of this carbocyclization. Importantly, this discovery enables a practical two‐step protocol switching the overall reaction of acetophenones with internal alkynes from a (3+2) to a (4+1) annulation. Chalcones can unusually serve as the precursors of acetophenones which then undergo formal (4+1) cyclization with internal alkynes via rhodium(III) catalysis in a regio‐ and chemoselective manner. 1‐Indanones containing quaternary carbon centers along with reusable aryl aldehydes were formed by this annulation. This discovery enables a practical two‐step protocol to indanones from the reaction of acetophenones with internal alkynes.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202305983