title: Mechanism selection for regiocontrol in base-assisted, palladium-catalysed direct C-H coupling with halides: first approach for oxazole- and thiazole-4-carboxylates.
abstract: Both base-assisted non-concerted metallation-deprotonation (nCMD) and concerted metallation-deprotonation (CMD) have been identified as two potent operating mechanisms in palladium-catalysed direct C-H coupling of oxazole and thiazole-4-carboxylate esters with halides through base- and solvent-effect experiments. Novel C2- and C5-selective CMD direct arylation procedures in oxazole- and thiazole-4-carboxylate series were then designed by controlling the balance between electronic and steric factors. Notably, charge interactions between the palladium catalyst and substrate were identified as a parameter for controlling selectivity and reducing the impact of steric factors in the CMD reaction.
authors.affiliation: Institut de Chimie Organique Fine associé au CNRS (UMR 6014), INSA et Université de Rouen, Place Emile Blondel, BP 08 76131 Mont Saint Aignan, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Théveau
authors.forename: Cécile
authors.initials: C
authors.lastname: Verrier
authors.forename: Pierrik
authors.initials: P
authors.lastname: Lassalas
authors.forename: Thibaut
authors.initials: T
authors.lastname: Martin
authors.forename: Georges
authors.initials: G
authors.lastname: Dupas
authors.forename: Olivier
authors.initials: O
authors.lastname: Querolle
authors.forename: Luc
authors.initials: L
authors.lastname: Van Hijfte
authors.forename: Francis
authors.initials: F
authors.lastname: Marsais
authors.forename: Christophe
authors.initials: C
authors.lastname: Hoarau
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D015394:Molecular Structure; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D010165:Palladium; D012997:Solvents; D013844:Thiazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; D010080:Oxazoles; D012997:Solvents; D013844:Thiazoles; D010165:Palladium