title: Multicomponent synthesis of 6H-dibenzo[b,d]pyran-6-ones and a total synthesis of cannabinol.
abstract: A multicomponent domino reaction that affords 6H-dibenzo[b,d]pyran-6-ones is reported. The overall transformation consists of six reactions: Knoevenagel condensation, transesterification, enamine formation, an inverse electron demand Diels-Alder (IEDDA) reaction, 1,2-elimination, and transfer hydrogenation. Both the diene and dienophile for the key inverse electron demand Diels-Alder (IEDDA) step are generated in situ by secondary amine-mediated processes. In most cases, the yields (10-79%) are considerably better than those obtained using a stepwise process. This methodology is employed in a concise total synthesis of cannabinol.
authors.affiliation: Department of Chemistry, Memorial University, St. John's, NL, Canada, A1B 3X7.
authors.forename: Penchal Reddy
authors.initials: PR
authors.lastname: Nandaluru
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Bodwell
mesh_terms: D002187:Cannabinol / Q000138:chemical synthesis*; D006865:Hydrogenation; D007783:Lactones / Q000138:chemical synthesis*; D015394:Molecular Structure; D010616:Phenanthrenes / Q000138:chemical synthesis*; D011714:Pyrans
chemical_list: D007783:Lactones; D010616:Phenanthrenes; D011714:Pyrans; C073118:6H-dibenzo-(b,d)-pyran-6-one; D002187:Cannabinol