Glucopyranoside-substituted imidazolium-based chiral ionic liquids for Pd-catalyzed homo-coupling of arylboronic acids in water

Abstract

Chiral ionic liquids (CILs) are widely used solvents and materials with prominent properties. Carbohydrate-derived imidazolium-based CILs represent a distinctive type of CILs possessing multiple chiral centers from natural chiral pool. Herein, a series of glucopyranoside-substituted imidazolium-based CILs (Glu-imi-CILs) were synthesized and evaluated as ligands for Pd-catalyzed homo-coupling reactions of arylboronic acids in water. The glucopyranoside substituent was instrumental for improving the catalytic activity of the resulting catalysts. Moreover, a Glu-imi-CIL with a free hydroxyl group for additional coordination was found to be the most efficient ligand. A series of symmetric biaryl compounds (13 examples) were synthesized from arylboronic acids by this method in high isolated yields (85−99%).

Keywords:

• Carbohydrate
• imidazolium-based ionic liquid
• palladium catalysts
• arylboronic acid
• homo-coupling
• green chemistry

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [No. 21562002], the Funding Project for Academic and Technical Leaders of Jiangxi Province [No. 20172BCB22021], Jiangxi Provincial Department of Education [GJJ170834], and Undergraduate Training Program for Innovation and Entrepreneurship [No. CX190009].