Trifluoromethoxylation of Allylic Alcohols via 1,2-Aryl Migration Promoted by Visible Light-Mediated Photoredox Catalysis

Sammanfattning: Visible light photoredox catalysis has proven to be a powerful tool for promoting transformations in organic synthesis. Hence this project was carried out to develop tools for predicting reactivity patterns of visible light- promoted redox reactions. Fluorination is of immense importance in organic chemistry, and so is trifluoromethoxylation. The fluorination reaction has been studied for a long time and has been accomplished in milder ways, while the generation of a trifluoromethoxy-radical at room temperature and atmospheric pressure remains a challenge. The design of the reaction in this project is to overcome the instability and take control of the catalytic event under visible- light photocatalytic conditions. The trifluoromethoxylation reaction proceeded at room temperature with the reaction time of 60 min using acetonitrile as the solvent and blue LED (10 W) as the external light source. No yield of the desired product was obtained for any of the substrates. More surprisingly, in all entries, 3,3-diphenylprop-2-en-1-ol was attained as a side product. The same side product was also detected in the entry with ambient light, concluding that the reaction was completed without any external light source. Thus, no photoredox catalysis took place.