Reaction of 1,2‐Difunctionalized Ethanes with Aryl Iodides in Copper‐catalyzed Cross‐Coupling: Application to Synthesis of Phenols

Abstract

A series of 1,2‐difunctionalized ethanes, such as ethylene glycol, 2‐aminoethanol, 1,2‐diaminoethane, 2‐dimethylaminoethanol, N′,N′‐dimethylethane‐1,2‐diamine, were investigated to test the reactivity with aryl iodides in the presence of copper catalysts. Under the reaction conditions, they produce the various C‐heteroatom cross‐coupled products. Interestingly, ethylene glycol and 2‐dimethylaminoethanol afforded mainly the phenolic compounds while the others produced different cross‐coupled products. Although ethylene glycol and 2‐dimethylaminoethanol resulted in the same product, their behaviors in the reaction were quite different: ethylene glycol appears to mostly act as the ligand and 2‐dimethylaminoethanol appears to serve as both the ligand and reactant. This finding led to a copper‐catalyzed synthesis of phenols using either ethylene glycol or 2‐dimethylaminoethanol, which can be applied to a variety of aryl iodides, providing an alternative synthetic route to phenols

Transition-metal-catalyzed synthesis of phenols and aryl thiols

“…In 2015, the Chae group found difunctionalized ethanes including 2-dimethylaminoethanol and ethylene glycol can function as ligand to work with Cu(OAc) 2 in the presence of KOH, affording phenols from aryl iodides in moderate to excellent yields (Scheme 17) [40]. …”