biostudies-literatureAllen EENational Institute of General Medical SciencesNIGMS NIH HHS1878-1881https://www.ebi.ac.uk/biostudies/studies/S-EPMC5716626biostudies-literatureUnknown19(7)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.Organic lettersMulticomponent Condensation Reactions via ortho-Quinone Methides.PMC5716626R01 GM078240P50 GM067041Schaus SEPanek JSAllen EEZhu CfalseMulticomponent Condensation Reactions via ortho-Quinone Methides.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.2017-01-01T00:00:00Z2017 Apr2025-04-18T18:06:00.064Z2019-03-26T23:25:51ZS-EPMC57166262835787010.1021/acs.orglett.7b00647