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Paper | Regular issue | Vol 55, No. 1, 2001, pp.135-144
Published online, 1st January, 1970
DOI: 10.3987/COM-00-9071
Diastereoselective Ring-Expansion Reaction of Methanochromanone with Aldehydes: Formation of trans-Fused Tetrahydrofuro[2,3-b][1]benzopyranones and Their Isomerization

Yoshiaki Sugita,* Kazuyoshi Kawai, and Ichiro Yokoe

*Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japana

Abstract

In the presence of SnCl4, 2,3-dimethoxycarbonylmethanochromanone (4) was transformed into a zwitter-ion which easily reacted with aldehydes to give the trans-fused tetrahydrofuro[2,3-b][1]benzopyranones in good yields with high diastereoselectivity. cis-Fused furobenzopyranone derivatives were also obtained in good yields by isomerization of the trans isomers.