Asymmetric Ni-Catalyzed Radical Relayed Reductive Coupling
Xiaofeng Wei, Wei Shu, Andrés García-Domínguez, Estíbaliz Merino and Cristina Nevado*
*Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich, CH 8057, Switzerland,
Email: cristina.nevado
chem.uzh.ch
X. Wei, W. Shu, A. García-Domínguez, E. Merino, C. Nevado, J. Am. Chem. Soc., 2020, 142, 13515-13522.
DOI: 10.1021/jacs.0c05254
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Abstract
A highly efficient asymmetric intermolecular Ni-catalyzed reductive dicarbofunctionalization of vinyl amides, vinyl boranes, or vinyl phosphonates with two distinct readily available electrophiles, namely, Csp2- and Csp3-halides, provides chiral products in a highly regio- and enantioselective manner.
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Details
The article discusses a highly efficient asymmetric intermolecular Ni-catalyzed reductive dicarbofunctionalization of alkenes, which enables the simultaneous addition of two distinct electrophiles (Csp2- and Csp3-halides) across various olefins (vinyl amides, vinyl boranes, vinyl phosphonates) at room temperature. This process, termed "asymmetric radical relayed reductive coupling" (ARRRC), avoids the use of sensitive organometallic reagents and relies on an in situ generated chiral alkyl Ni(III)-intermediate to ensure stereodefined outcomes. The use of a (L)-(+)-isoleucine chiral bisoxazoline ligand and the presence of coordinating sites on the alkene are crucial for the reaction's success. The methodology showcases high regio- and enantioselectivity and is applicable to a wide range of substrates, including iodoarenes and tertiary alkyl iodides. The resulting chiral amides can be further transformed into valuable chiral building blocks such as primary and secondary amines and oxazolines. The article also highlights the synthetic utility of this new methodology and provides detailed mechanistic insights supported by DFT calculations. The research was supported by the European Research Council and the Swiss National Science Foundation.
Key Words
benzylic amines, alkylation, multicomponent reactions, TDAE
ID: J48-Y2020
