The use of Hagemann's esters to prepare highly functionalized phenols and benzenes

Hagemann's esters can be converted into highly functionalized phenols or arenes.The systematic functionalization of Hagemann's ester derivatives permits the preparation of tri-and tetraalkylsubstituted phenols or tetra-, penta-, and hexaalkyl-substituted benzenes.Kotnis's aromatization procedure was found to be solvent dependent, and Suzuki couplings were found to be sensitive to steric hindrance.Wittig olefination and ortho-Claisen reactions were reliable means to introduce alkyl substituents at C-4 and/or C-5 positions, respectively.The acid-promoted dehydration of tertiary alcohol 46 to produce enone 47, followed by its selective alkylation (cf.48) is new.