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Cu-catalyzed enantioconvergent deborylative alkynylation
Joshua F Head1, Tanner J Schubert1, Biyu Zhao1
1Department of Chemistry, Colorado State University Fort Collins Colorado 80523 USA Yuyang.Dong@colostate.edu.
Chemical Science
|October 6, 2025
Summary
This study introduces a novel copper-catalyzed method for creating chiral alkynes from alkylboronic pinacol esters. This deborylative strategy offers good enantioselectivity and broad functional group tolerance.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Alkylboronic pinacol esters are versatile synthetic reagents.
- Their use in asymmetric C-C cross-coupling remains limited.
- Developing new methods for chiral alkyne synthesis is crucial.
Purpose of the Study:
- To develop a copper-catalyzed deborylative strategy for synthesizing α-chiral alkynes.
- To explore the direct application of alkylboronic pinacol esters in asymmetric C-C cross-coupling.
- To achieve high enantioselectivity and functional group tolerance.
Main Methods:
- Copper-catalyzed deborylative cross-coupling reaction.
- Radical clock ring-opening studies.
- Radical trapping experiments.
- Enantioconvergence tests.
- Density Functional Theory (DFT) calculations.
Main Results:
- Successful synthesis of α-chiral alkynes with good enantioselectivity.
- Broad substrate scope, including various functional groups and heterocycles.
- Proposed radical-relay mechanism involving aminyl radical C-B bond cleavage and Cu-catalyzed alkynylation.
- DFT calculations supported a Cu-mediated inner-sphere C-C bond formation.
Conclusions:
- A novel and efficient Cu-catalyzed deborylative method for α-chiral alkyne synthesis has been established.
- The reaction proceeds via a radical-relay pathway.
- Ligand-substrate halogen-π interactions are key to achieving enantioselectivity.
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