Synthesis and Lewis acid induced isomerization of mono-, di-, and tri-spiro α-keto tetrahydro-furans and-pyrans

…, PR Selvaraj, LA Paquette

Index: Hilmey, David G.; Selvaraj, Peter R.; Paquette, Leo A. Canadian Journal of Chemistry, 2006 , vol. 84, # 10 p. 1388 - 1396

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Abstract

The stereoselectivity of the acid-catalyzed ring expansion of dihydrofuranyl and dihydropyranyl 1, 2-adducts to spirocyclic ketones 8 and 9 has been examined. These substrates have become readily available by the utilization of 1, 3-dichloroacetone as a synthetic equivalent of cyclopropanone. The kinetically controlled isomerizations result in ring expansion to dispirocyclopentanones. Third-stage conversion to ...