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Ligand‐Free Copper‐Catalyzed Ullmann‐Type C−O Bond Formation in Non‐Innocent Deep Eutectic Solvents under Aerobic Conditions
Author(s) -
Quivelli Andrea Francesca,
Marinò Manuela,
Vitale Paola,
GarcíaÁlvarez Joaquín,
Perna Filippo M.,
Capriati Vito
Publication year - 2022
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202102211
Subject(s) - chemistry , catalysis , aryl , alkyl , choline chloride , ligand (biochemistry) , yield (engineering) , eutectic system , halide , copper , deep eutectic solvent , organic chemistry , solvent , ether , polymer chemistry , medicinal chemistry , materials science , alloy , metallurgy , biochemistry , receptor
An efficient and novel protocol was developed for a Cu‐catalyzed Ullmann‐type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride‐based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [Cu I or Cu II species] loading up to 5 mol% and K 2 CO 3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70–96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E‐factor as low as 5.76.