Synfacts 2018; 14(09): 0929
DOI: 10.1055/s-0037-1610578
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Copper-Catalyzed Defluoroalkylation

Rezensent(en):
Mark Lautens
,
Andrew Whyte
Wang M. Pu X. Zhao Y. Wang P. Li Z. Zhu C. Shi Z. * Nanjing University, P. R. of China
Enantioselective Copper-Catalyzed Defluoroalkylation Using Arylboronate-Activated Alkyl Grignard Reagents.

J. Am. Chem. Soc. 2018;
140: 9061-9065
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Publikationsverlauf

Publikationsdatum:
20. August 2018 (online)

 

Significance

Defluorination of trifluoromethyl alkenes has become a popular strategy in the past few years to introduce a new stereocenter and synthesize gem-difluoroalkenes. gem-Difluoroalkenes are useful handles for further functionalizations and they are also useful moieties in medicinal chemistry. Shi and co-workers report the enantioselective addition of alkyl Grignard reagents to trifluoromethyl alkenes with the assistance of an arylboronate.


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Comment

The reaction uses alkyl magnesium bromide reagents which initially react with the organoboron species to form a tetraorganoborate. The tetraalkylboron species reacts with the copper catalyst to undergo an enantioselective addition to the trifluromethyl alkene followed by β-fluoride elimination. The reaction was successful with a variety of substituents on the trifluoromethyl alkenes including aryl, alkenyl, alkynyl, and alkyl groups. Unfunctionalized Grignard reagents were most extensively investigated in the reaction.


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