title: Regioselective Tandem [4 + 1]-[4 + 2] Synthesis of Amino-Substituted Dihydroxanthones and Xanthones.
abstract: A highly convergent and operationally simple approach to mycotoxin-related 4-amino-substituted 1-hydroxydihydroxanthones is described. The target compounds are obtained in one pot by the multicomponent reaction of 3-carbonylchromones, isocyanides, and nonsymmetric dienophiles. The reaction, which involves a tandem [4 + 1]-[4 + 2] cycloaddition, efficiently affords a variety of both monomeric and dimeric polysubstituted dihydroxanthones structurally similar to bioactive ergochromes. Further aromatization to the corresponding xanthones is readily achieved by treatment with DBU under microwave irradiation.
authors.forename: Ana
authors.initials: A
authors.lastname: Bornadiego
authors.forename: Jesús
authors.initials: J
authors.lastname: Díaz
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Marcos
mesh_terms: D002384:Catalysis; D061565:Cycloaddition Reaction; D008872:Microwaves; D015394:Molecular Structure; D013237:Stereoisomerism; D044004:Xanthones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D044004:Xanthones