title: Synthesis of functional heterocycles via tandem reaction.
abstract: Tandem reactions for efficient construction of nitrogen-containing heterocycles were developed. One-pot platinum(II)-catalyzed synthesis of indoles and isoquinolines has been achieved via isocyanates, which were derived from a Hofmann-type rearrangement of 2-alkynylbenzamides and 2-alkynylbenzylamides using a hypervalent iodine reagent. As an extension of this approach, trans-2,3-dihydro-4-quinolones were synthesized via acid-catalyzed intermolecular [2+2]-cycloaddition of aldehydes and carbamates, which were formed from nucleophilic addition of alcohols to isocyanate intermediates. Direct, efficient syntheses of the benzimidazo[2,1-a]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5-endo cyclization, oxidative aromatization, and 6-endo cyclization can be performed in a single synthetic operation.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hirokoshingai, Kure, Hiroshima 737-0112, Japan. n-okamo@ps.hirokoku-u.ac.jp
authors.forename: Noriko
authors.initials: N
authors.lastname: Okamoto
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry; D055598:Chemical Phenomena; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D007211:Indoles / Q000737:chemistry; D007546:Isoquinolines / Q000737:chemistry; D015363:Quinolones / Q000737:chemistry
chemical_list: D001562:Benzimidazoles; D006571:Heterocyclic Compounds; D007211:Indoles; D007546:Isoquinolines; D015363:Quinolones; C427107:benzimidazo(2,1-a)isoquinoline; C039109:isoquinoline