Zirconium-Mediated Enantioselective Darzens Reaction

Significance

Enantiomerically enriched glycidic esters and amides constitute an important class of building blocks for organic synthesis. The Darzens reaction represents a powerful approach towards these compounds; however, limited success has been achieved for asymmetric versions of the process. The authors have developed an air-staible zirconium-based catalytic system, which allowed the formation of glycidic amides with 64-97% yields and 91 to >99% ee. cis-Adducts were formed exclusively. This methodology is advantageous to titanium-based systems with regard to lesser sensitivity to air and moisture. A wide range of substrates was tolerated including aromatic, heteroaromatic, and aliphatic aldehydes.