Quaternary ammonium (hypo)iodite catalysis for enantioselective oxidative cycloetherification

Area of Science:

• Organic Chemistry
• Green Chemistry
• Catalysis

Background:

• Minimizing toxic/rare metals in pharmaceutical synthesis is crucial.
• Hypervalent iodine compounds offer greener alternatives but have limited catalytic applications, especially in asymmetric synthesis.

Purpose of the Study:

• To develop an enantioselective oxidative cycloetherification of ketophenols.
• To utilize environmentally benign catalysts and oxidants for synthesizing 2-acyl-2,3-dihydrobenzofuran derivatives.

Main Methods:

• In situ generation of chiral quaternary ammonium hypoiodite salts.
• Catalytic enantioselective oxidative cycloetherification using hydrogen peroxide as the oxidant.
• Synthesis of optically active 2-acyl-2,3-dihydrobenzofuran derivatives from ketophenols.

Main Results:

• Successful enantioselective oxidative cycloetherification of ketophenols was achieved.
• Chiral quaternary ammonium hypoiodite salts effectively catalyzed the transformation.
• Hydrogen peroxide served as an efficient and green oxidant.

Conclusions:

• The developed method provides an environmentally benign catalytic approach for synthesizing chiral 2-acyl-2,3-dihydrobenzofuran derivatives.
• This methodology expands the utility of hypervalent iodine compounds in asymmetric catalysis.
• The synthesized compounds are valuable scaffolds for biologically active molecules.