The selected bisphenol candidates based on phenol, guaiacol, and syringol were synthesized using Lewis or Brønsted acid catalysis (Figure ). For accessing bisphenols with up to one carbon substituent on the bridging methylene carbon, we adapted a procedure from our previous work on deoxygenative functionalization of benzylic alcohols. In this catalytic approach, Friedel-Crafts-type alkylation of benzylic alcohols is catalyzed by moisture-tolerant zirconium-or hafnium-based metal salts under close to ambient conditions. Optimization of the reaction conditions for the synthesis of targeted bisphenol candidates included selection of the optimal catalyst, transition to 2-methyltetrahydrofuran (2-MeTHF) as a renewable solvent, and optimization of the catalyst and reactant concentrations for efficient and selective formation of the desired products. The bisphenols with up to two substituents on the bridging methylene carbon were synthesized with a more conventional Brønsted acid-catalyzed approach. Both protocols provided the expected products in reasonable yields, while several of the bisphenols were formed as a mixture of p,p'/m,p'-regioisomers (Figure ). The latter were separated as individual compounds by column chromatography prior to the in vitro toxicological assays, unless otherwise noted.