title: Palladium-catalyzed direct heck arylation of dual pi-deficient/pi-excessive heteroaromatics. Synthesis of C-5 arylated imidazo[1,5-a]pyrazines.
abstract: A general and efficient synthesis of 5-aryl imidazo[1,5- a]pyrazines by palladium-catalyzed coupling of the corresponding 8-substituted derivatives with aryl halides is described. The scope of this new reaction for the imidazo[1,5- a]pyrazine ring system was explored using three readily available 8-substituted precursors, X = NH2, NMe2, and OMe, as well as 8-aryl derivatives, X = Ar'. On the basis of these results as well as studies using a deuterated derivative, a Heck-like mechanism is proposed for this transformation.
authors.affiliation: Department of Chemistry, Queen's University, Kingston, Ontario, Canada.
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Wang
authors.forename: J Adam
authors.initials: JA
authors.lastname: McCubbin
authors.forename: Meizhong
authors.initials: M
authors.lastname: Jin
authors.forename: Radoslaw S
authors.initials: RS
authors.lastname: Laufer
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Mao
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Crew
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Mulvihill
authors.forename: Victor
authors.initials: V
authors.lastname: Snieckus
mesh_terms: D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D011719:Pyrazines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D006842:Hydrocarbons, Brominated; D007093:Imidazoles; D011719:Pyrazines; D010165:Palladium