title: Cobalt-catalyzed intramolecular [2 + 2 + 2] cocyclotrimerization of nitrilediynes: an efficient route to tetra- and pentacyclic pyridine derivatives.
abstract: [reaction: see text] In this paper, we wish to report the intramolecular [2 + 2 + 2] cocyclotrimerization of nitrilediynes catalyzed by the CoI2(dppe)/Zn system at 80 degrees C in CH3CN. Under these reaction conditions, various highly substituted nitrilediynes having steric conjunction at the alpha and beta positions to a nitrile group and a bulkier substitution at the terminal carbon of alkyne undergo [2 + 2 + 2] cocylotrimerization to afford tetra- and pentacyclic pyridine derivatives in good to excellent yields.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Masilamani
authors.initials: M
authors.lastname: Jeganmohan
authors.forename: Chien-Hong
authors.initials: CH
authors.lastname: Cheng
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D003500:Cyclization; D007454:Iodides / Q000737:chemistry; D008956:Models, Chemical; D009570:Nitriles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013696:Temperature; D015032:Zinc / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000480:Alkynes; D007454:Iodides; D009570:Nitriles; D011108:Polymers; D011725:Pyridines; D003035:Cobalt; D002244:Carbon; D015032:Zinc