Substituent Effect on Claisen Rearrangement of 1-Substituted 2-Cinnamyloxybenzenes

Abstract

Claisen rearrangement of 1-substituted 2-cinnamyloxybenzenes was carried out in decalin. For methyl-, acetyl- and methoxycarbonyl derivatives, the para-rearranged product was predominant. Reactions of nitro- and carboxyl derivatives were relatively fast and produced ortho-rearranged products. For other derivatives, intramolecular hydrogen bonds formed so that keto-enol tautomerism between the ortho-dienone intermediate and ortho-rearranged product proceeded smoothly.