Palladium(II)‐Catalyzed Intramolecular 1,4‐Oxyacyloxylation of Conjugated Dienes. A Stereocontrolled Route to Fused Six‐Membered Lactones and Pyrans.

Abstract

Palladium(II)-Catalyzed Intramolecular 1,4-Oxyacyloxylation of Conjugated Dienes. A Stereocontrolled Route to Fused Six-Membered Lactones and Pyrans.-It is found that Pd-catalyzed intramolecular 1,4-oxyacyloxylation of conjugated dienes is a useful method to prepare fused 6-membered lactones and pyrans. The regio-and stereoselectivity can be controlled by the presence or absence of Li salts as well as solvent composition. The resulting products are important synthons which can be transformed into cis-or trans-fused 6-membered systems. In contrast, fused 7-membered lactones cannot be prepared under these conditions and 1,4-oxidative cyclization of dienyl amide analogues is unsuccessful. -(VERBOOM, R. C.; PERSSON, B. A.; BAECKVALL*, J.-E.; J. Org. Chem. 69 (2004) 9, 3102-3111; Dep. Org. Chem., Arrhenius Lab., Univ. Stockholm, S-106 91 Stockholm, Swed.; Eng.) -Jannicke 36-125