Synthesis of Dihydrobenzofurans via Palladium-Catalyzed Annulation of 1,3-Dienes by o-Iodoaryl Acetates

• Published in: Journal of organic chemistry 2010-06, Vol.75 (12), p.4131-4134
• Main Authors: Rozhkov, Roman V, Larock, Richard C
• Format: Article
• Language: English
• Subjects: Acetates - chemistry; Alkadienes - chemistry; Benzofurans - chemical synthesis; Benzofurans - chemistry; Catalysis; Catalysts: preparations and properties; Chemistry; Coordination compounds; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Inorganic chemistry and origins of life; Iodine - chemistry; Molecular Structure; Noncondensed benzenic compounds; Organic chemistry; Palladium - chemistry; Preparations and properties; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo100495t

The palladium-catalyzed annulation of 1,3-dienes by o-iodoaryl acetates provides an efficient approach to biologically interesting dihydrobenzofurans. The annulation is believed to proceed via (1) oxidative addition of the aryl iodide to Pd(0), (2) syn-addition of the resulting arylpalladium complex to the 1,3-diene, (3) intramolecular coordination of the phenolic oxygen to the Pd center, (4) hydrolysis of the acetyl group, and (5) reductive elimination of Pd(0), which regenerates the catalyst. This reaction is quite general, regioselective, and stereoselective, and a wide variety of terminal, cyclic, and internal 1,3-dienes, as well as electron-rich and electron-deficient o-iodoaryl acetates, can be utilized.