title: Palladium(II)-catalyzed synthesis of 2H,3'H-spiro[benzofuran-3,2'-naphthoquinones].
abstract: 2H,3'H-Spiro[benzofuran-3,2'-naphthoquinones], constituting a new spiroheterocyclic skeleton, were synthesized starting from 2-aryloxymethyl-1,4-naphthoquinones by means of a palladium(II)-catalyzed reaction, which is a new spirocyclic transformation. Under optimal conditions, i.e. 10 mol % of palladium(II) acetate, 15 mol % of 3,5-dichloropyridine, and 5 mol % of trifluoroacetic acid in acetic acid at 110 °C, various 2H,3'H-spiro[benzofuran-3,2'-naphthoquinones] were synthesized in yields strongly dependent on the substitution pattern of the aryloxy group. Unsubstituted or ortho-substituted 2-aryloxymethyl-1,4-quinones were found to rearrange toward the corresponding 2-(4-hydroxyaryl)-1,4-quinones upon treatment with trifluoroacetic acid.
authors.affiliation: Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Claes
authors.forename: Jan
authors.initials: J
authors.lastname: Jacobs
authors.forename: Bart
authors.initials: B
authors.lastname: Kesteleyn
authors.forename: Tuyen
authors.initials: T
authors.lastname: Nguyen Van
authors.forename: Norbert
authors.initials: N
authors.lastname: De Kimpe
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001572:Benzofurans; D009285:Naphthoquinones; D009942:Organometallic Compounds; D013141:Spiro Compounds; D010165:Palladium