title: Synthesis of substituted pyridines from cascade [1 + 5] cycloaddition of isonitriles to N-formylmethyl-substituted enamides, aerobic oxidative aromatization, and acyl transfer reaction.
abstract: A novel strategy for de novo synthesis of pyridines featuring an unprecedented α-addition of aldehyde and enamide to isonitrile as a key step is described. Under mild conditions, a cascade reaction involving Zn(OTf)2-promoted [1 + 5] cycloaddition of isonitrile with N-formylmethyl-substituted enamide, facile aerobic oxidative aromatization and intermolecular acyl transfer from the pyridinium nitrogen to the 5-hydroxy oxygen, and finally acylation of the 4-amino group by an external acyl chloride efficiently afforded 2-substituted 4-acylamino-5-acyloxypyridines in good to excellent yields.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Chuan-Hu
authors.initials: CH
authors.lastname: Lei
authors.forename: De-Xian
authors.initials: DX
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.forename: Jieping
authors.initials: J
authors.lastname: Zhu
authors.forename: Mei-Xiang
authors.initials: MX
authors.lastname: Wang
mesh_terms: D000215:Acylation; D000447:Aldehydes / Q000138:chemical synthesis / Q000737:chemistry*; D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry*; D061565:Cycloaddition Reaction; D009570:Nitriles / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000577:Amides; D009570:Nitriles; D011725:Pyridines