A Novel Cycloaromatization Reaction. Regiocontrolled Synthesis of Substituted Methyl Salicylates

Article abstract of DOI:10.1021/ja00530a038

A new method of constructing six-membered rings, involving the condensation of two three-carbon units, one with two nucleophilic sites and the other containing two electrophilic sites, is reported.The regiochemistry of the reaction is controlled by the differential reactivities of these sites. 1,3-Bis(trimethylsiloxy)-1-methoxybuta-1,3-diene (1) constitutes the three-carbon fragment with two nucleophilic sites.Condensation of 1 with various equivalents of β-dicarbonyl compounds and titanium tetrachloride gave substituted methyl salicylates.The regiochemistry is controlled by the order of reactivity of the electrophilic sites, which is conjugate position of enone > ketone > monothioacetal, acetal.