Diastereoselective Spiroannulation of Phenolic Derivatives: Effect of Steric Hindrance on the Diastereoselectivity

This study was aimed at determining the effect, if any, that steric factors may have on the diastereoselectivity in the spiroannulation of simple phenols. A series of phenols bearing different size substituents ortho to the phenolic hydroxyl were synthesized and spiroannulated to the corresponding spiroethers in good to excellent yields (76-94%). However, the diastereoselectivity of the reaction remain mostly unchanged suggesting that stereoelectronic rather then steric factors influence the diastereoselectivity in this reaction.