Selective Palladium-Catalyzed C–F Activation/Carbon–Carbon Bond Formation of Polyfluoroaryl Oxazolines

Abstract

A selective palladium-catalyzed Suzuki-Miyaura coupling reaction of polyfluorophenyl oxazolines through ortho C-F activation is described. It was found that reactions with DPPF as the ligand occurred much faster than those with other ligands. A variety of arylboronic acids including challenging functionalized arylboronic acids such as enolizable ketones, aldehyde, cyano, ester, and trifluoromethyl groups were tolerated with the reaction conditions.

ChemInform Abstract: Palladium‐Catalyzed ortho‐Selective C—F Activation of Polyfluoroarenes with Triethylsilane: A Facile Access to Partially Fluorinated Aromatics.

“…Further investigation revealed that only trace amount of desired product 3 e was observed under catalytic reaction conditions (Scheme 2 b). [20] As shown in Scheme 3, compounds 7 and 8 can be easily prepared by palladium-catalyzed cross-coupling of 1 or 5 with various aryl and alkenyl species including boronic acids, borates and silanes. As to the formation of II-2, we reasoned that when [{PdCl(C 3 H 5 )} 2 ] was treated with Et 3 SiH and dppe, besides the formation of Pd 0 species, Et 3 SiCl was also generated.…”

“…To illustrate the potential applications of this method, the construction of C À C bond by C À F bond activation has also been examined. [20] As shown in Scheme 3, compounds 7 and 8 can be easily prepared by palladium-catalyzed cross-coupling of 1 or 5 with various aryl and alkenyl species including boronic acids, borates and silanes.…”

Activation and Formation of Aromatic C–F Bonds

“…75) [132]. The transformation was tolerant to a large selection of functional groups including cyano, ester, ketones, aldehydes, and trifluoromethyl groups.…”

Palladium-Mediated Organofluorine Chemistry

“…In this case the same trends as those mentioned for the nitro derivatives are observed: Selective functionalization of the ortho fluorine and lower reactivity as the number of fluorine atoms in the ring decrease. 235 The same authors reported an interesting coupling that involves a C-H activation of the non-fluorinated partner (Scheme 76, L = diphosphine). 236 In this case a 2-pyridinyl group as directing group was more effective than the oxazoline used before.…”