A general route to α-pyrones and 3-substitutedisocoumarins from (Z)-iodovinylic acids 1a−f or 2-iodobenzoic acids 4a−c is described, including compounds bearing a substituent on the aromatic ring. Treatment of (Z)-β-iodovinylic acids 1a−f or 2-iodobenzoic acids 4a−c with various allenyltributyltin reagents in the presence of palladium acetate, triphenylphosphine, and tetrabutylammonium bromide in
A new protocol for the synthesis of polysubstituted isocoumarins from 2-iodobenzoic acid and beta-diketone compounds has been developed. The occurrence of C-arylation cyclization reaction in transition-metal-free systems and ortho-induced substrates has been exploited. Reactions using these inexpensive conditions have displayed high functional group tolerance and excellent yields. (c) 2012 Elsevier Ltd. All rights reserved.