title: Brønsted Acid-promoted intramolecular carbocyclization of alkynals leading to cyclic enones.
abstract: TFA-promoted exo carbocyclizations of nonterminal 7-alkynals gave good to excellent yields of seven-membered cycloalkenones, a medium-sized functionalized ring present in natural products with relevant pharmacological properties. Nonterminal 5- and 6-alkynals also gave very good yields of the corresponding exo cyclopentenones and cyclohexenones. On the other hand, terminal 5-alkynals gave endo carbocyclizations to cyclohexenones. These carbocyclizations can be considered as tandem alkyne hydration/aldol condensation processes.
authors.affiliation: Departamento de Quimica Organica, Facultad de Quimica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: González-Rodríguez
authors.forename: Luz
authors.initials: L
authors.lastname: Escalante
authors.forename: Jesús A
authors.initials: JA
authors.lastname: Varela
authors.forename: Luis
authors.initials: L
authors.lastname: Castedo
authors.forename: Carlos
authors.initials: C
authors.lastname: Saá