E. Wang, Tzu-Wei Tsai, Keng-Shiang Huang
Aug 1, 2004
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Influential Citations
17
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Journal
Heterocycles
Abstract
Substituted benzofurans derived from isovanillin were synthesized. 2-Allyl-3-alkoxy-4-methoxyphenol, prepared from isovanillin via the Claisen rearrangement, O-alkylation and Baeyer-Villiger oxidation, were chloroethylated by two-phase reaction to furnish 1-allyl-3-alkoxy-(2-chloroethoxy)-4-methoxy- benzenes. The given compounds were treated with potassium tert-butoxide to undergo the isomerization of O-allyl group and dehydrochlorination of 2-chloroethoxy group to efficiently construct the precursors with C-propenyl- O-vinyl function for the ring-closing metathesis (RCM) in one pot. Then, then precursors were subjected to RCM to furnish 4,5-O-difunctionalized benzofurans in good over-all yield, respectively.