title: Metal-free one-pot synthesis of benzofurans.
abstract: Ethyl acetohydroxamate was efficiently arylated with diaryliodonium salts at room temperature under transition-metal-free conditions. The obtained O-arylated products were reacted in situ with ketones under acidic conditions to yield substituted benzo[b]furans through oxime formation, [3,3]-rearrangement, and cyclization in a fast and operationally simple one-pot fashion without using excess reagents. Alternatively, the O-arylated products could be isolated or transformed in situ to aryloxyamines or O-arylaldoximes. The methodology was applied to the synthesis of Stemofuran A and the formal syntheses of Coumestan, Eupomatenoid 6, and (+)-machaeriol B.
authors: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm (Sweden), Fax: (+46) 8-15-4908.
authors: Raju
authors: R
authors: Ghosh
authors: Elin
authors: E
authors: Stridfeldt
authors: Berit
authors: B
authors: Olofsson
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D010091:Oximes / Q000138:chemical synthesis / Q000737:chemistry; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001572:Benzofurans; D001578:Benzopyrans; D003374:Coumarins; D010091:Oximes; D010636:Phenols; C440676:machaeriol B; C489063:stemofuran A; C452812:eupomatenoid 6; C505898:coumestan
keywords: O-aryloximes; arylation; aryloxyamines; cyclization; diaryliodonium salts; sigmatropic rearrangement