title: Multicomponent Condensation Reactions via ortho-Quinone Methides.
abstract: Iron(III) salts promote the condensation of aldehydes or acetals with electron-rich phenols to generate ortho-quinone methides that undergo Diels-Alder condensations with alkenes. The reaction sequence occurs in a single vessel to afford benzopyrans in up to 95% yield. The reaction was discovered while investigating a two-component strategy using 2-(hydroxy(phenyl)methyl)phenols to access the desired ortho-quinone methide in a Diels-Alder condensation. The two-component condensation also afforded the corresponding benzopyran products in yields up to 97%. Taken together, the two- and three-component strategies using ortho-quinone methide intermediates provide efficient access to benzopyrans in good yields and selectivities.
authors.affiliation: Department of Chemistry, Center for Molecular Discovery (BU-CMD), Life Science and Engineering Building, Boston University , 24 Cummington Mall, Boston, Massachusetts 02215, United States.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Allen
authors.affiliation: Department of Chemistry, Center for Molecular Discovery (BU-CMD), Life Science and Engineering Building, Boston University , 24 Cummington Mall, Boston, Massachusetts 02215, United States.
authors.forename: Calvin
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Department of Chemistry, Center for Molecular Discovery (BU-CMD), Life Science and Engineering Building, Boston University , 24 Cummington Mall, Boston, Massachusetts 02215, United States.
authors.forename: James S
authors.initials: JS
authors.lastname: Panek
authors.affiliation: Department of Chemistry, Center for Molecular Discovery (BU-CMD), Life Science and Engineering Building, Boston University , 24 Cummington Mall, Boston, Massachusetts 02215, United States.
authors.forename: Scott E
authors.identifier: 0000-0002-5877-6587
authors.initials: SE
authors.lastname: Schaus
mesh_terms: D005290:Ferric Compounds; D045563:Indolequinones / Q000737:chemistry*; D015394:Molecular Structure; D010636:Phenols
chemical_list: D005290:Ferric Compounds; D045563:Indolequinones; D010636:Phenols; C068040:quinone methide