Synthesis of Polyfunctionalized Bicyclo [5.3. 1] undecadiene Ring Systems Using a Two??Carbon Ring??Expansion of Cyclobutene Intermediates

G Mislin, M Miesch

Index: Mislin, Gaetan; Miesch, Michel European Journal of Organic Chemistry, 2001 , # 9 p. 1753 - 1759

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Citation Number: 5

Abstract

Abstract The ZrCl 4-catalyzed [2+ 2] cycloaddition of the silyl enol ether derived from monoprotected bicyclo [3.3. 1] nonane-2, 6-dione 7 with ethyl propynoate led after acidic treatment to the cyclobutene derivative 12. Treatment of the latter with HBF 4 in refluxing ethanol smoothly afforded the two-carbon ring-expansion product 13. On the other hand, the enolate of the β-oxobicyclo [3.3. 1] nonane ester 14 has been found to react with ...