title: Catalyst-Switchable Regiocontrol in the Direct Arylation of Remote C-H Groups in Pyrazolo[1,5-a]pyrimidines.
abstract: The regiodivergent palladium-catalyzed C-H arylation of pyrazolo[1,5-a]pyrimidine has been achieved, wherein the switch in regioselectivity between positions C3 and C7 is under complete catalyst control. A phosphine-containing palladium catalyst promotes the direct arylation at the most acidic position (C7), whereas a phosphine-free catalyst targets the most electron-rich position (C3).
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK). r.bedford@bristol.ac.uk.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Bedford
authors.affiliation: Vertex Pharmaceuticals Ltd. (Europe), 86-88 Jubilee Avenue, Milton Park, Abingdon, Oxfordshire, OX14 4RW (UK).
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Durrant
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK).
authors.forename: Michelle
authors.initials: M
authors.lastname: Montgomery
mesh_terms: D002384:Catalysis; D010165:Palladium / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry; D011720:Pyrazoles / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D010720:Phosphines; D011720:Pyrazoles; D011743:Pyrimidines; C527752:pyrazolo(1,5-a)pyrimidine; D010165:Palladium; C044646:phosphine
keywords: CH activation; arylation; catalysis; palladium; regiocontrol