Studying Regioisomer Formation in the Pd-Catalyzed Fluorination of Aryl Triflates by Deuterium Labeling

Isotopic labeling has been used to determine that a portion of the desired product in the Pd-catalyzed fluorination of electron-rich, non-ortho-substituted aryl triflates results from direct C–F cross-coupling. In some cases, formation of a Pd-aryne intermediate is responsible for producing undesire...

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Bibliographic Details
Main Authors: Milner, Phillip John, Kinzel, Tom, Zhang, Yong, Buchwald, Stephen Leffler
Other Authors: Massachusetts Institute of Technology. Department of Chemistry
Format: Article
Language:en_US
Published: American Chemical Society (ACS) 2015
Online Access:http://hdl.handle.net/1721.1/99657
https://orcid.org/0000-0003-3875-4775
Description
Summary:Isotopic labeling has been used to determine that a portion of the desired product in the Pd-catalyzed fluorination of electron-rich, non-ortho-substituted aryl triflates results from direct C–F cross-coupling. In some cases, formation of a Pd-aryne intermediate is responsible for producing undesired regioisomers. The generation of the Pd-aryne intermediate occurs primarily via ortho-deprotonation of a L·Pd(Ar)OTf (L = biaryl monophosphine) species by CsF and thus competes directly with the transmetalation step of the catalytic cycle. Deuterium labeling studies were conducted with a variety of aryl triflates.