title: Copper(II)-catalyzed indolizines formation followed by dehydrogenative functionalization cascade to synthesize 1-bromoindolizines.
abstract: A one-pot, three-component cascade reaction between pyridine, α-acylmethylbromide, and maleic anhydride leading to direct access of 1-bromoindolizines in high yields has been developed. This protocol is accomplished via a reaction sequence of 1,3-dipolar cycloaddition of the pyridinium ylide with maleic anhydride, oxidative decarboxylation of the primary cycloadduct, and dehydrogenative bromination of the resulting 1-unsubstituted indolizine. Copper chloride was used as a catalyst and oxygen as the terminal oxidant. This reaction represents the first example of transition-metal-catalyzed direct dehydrogenative bromination of indolizine at the C-1 position. Moreover, the obtained 1-bromoindolizines can be transformed to other 1-substituted indolizines such as 1-arylindolizines via a simple reaction process.
authors.affiliation: Jiangsu Key Laboratory of Green Synthetic for Functional Materials and School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou 221116, Jiangsu, P. R. China.
authors.forename: Fuyao
authors.initials: F
authors.lastname: Wang
authors.forename: Yongmiao
authors.initials: Y
authors.lastname: Shen
authors.forename: Huayou
authors.initials: H
authors.lastname: Hu
authors.forename: Xiangshan
authors.initials: X
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D061565:Cycloaddition Reaction; D003653:Decarboxylation; D054879:Halogenation; D007212:Indolizines / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D007212:Indolizines; D003300:Copper