title: Gold-catalyzed cycloisomerization of alk-4-yn-1-ones.
abstract: Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans , whereas a 6-endo-dig cyclization to 4H-pyrans is observed with substrates bearing two substituents at C-3. In alcoholic solvents, alkylidene/benzylidene-substituted tetrahydrofuranyl ethers are formed in a tandem nucleophilic addition/cycloisomerization.
authors.affiliation: Dortmund University of Technology, Organic Chemistry, Otto-Hahn-Strasse 6, D-44227, Dortmund, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Belting
authors.forename: Norbert
authors.initials: N
authors.lastname: Krause
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D004987:Ethers; D005663:Furans; D007659:Ketones; D011714:Pyrans; D006046:Gold