Fluorinated phenylboronic acids

Tetrahydropyran-2-yl (THP)-protected 6-chloropurine l32 and bis(THP)-protected 2-amino-6-chloropurine 2,33 as well as 2, 3, 5 () (riacetyl 6-chloropurine riboside 334 and its 2 amino 6 chloropurine analogue 435 were chosen as suitable starting compounds for the cross coupling reactions with unsubstituted and fluorinated phenylboronic acids 5a—d. Due to the lability of the... 

Keywords Aryl bromides, fluorinated phenylboronic acids, ds-Pd(Ph2PCH2COO)2, K3PO4, THF-H2O, room temperature, Suzuki coupling, fluorinated biphenyl derivatives... 

A 25 mL two-neck flask was charged with 4-subtitited phenyl bromide (1 1 mmol), fluorinated phenylboronic acid (2 1.5 mmol), K3PO4.3H2O (3.0 mmol), cts-Pd(Ph2PCH2COO)2... 

An efficient aqueous phase Suzuki-Miyaura reaction of activated aryl chlorides with aryl boronic acids has been reported. The method uses a new D-glucosamine-based dicyclohexylarylphosphine ligand for the palladium catalyst and works well with nitro-and cyano-activated chlorides.32 The aryl fluoride bond has been considered inert to palladium-catalysed substitution reactions. However, a computational study, backed up by experiment, shows that the presence of a carboxylate group ortho to fluorine will allow reaction both with phenylboronic acids in a Suzuki-type reaction and with organotin reagents in a Stille-type reaction the presence of the adjacent oxyanion stabilizes the transition state.33... 

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