Review on Asymmetric Catalysis Employing 5H-Oxazol-4-Ones as α-Hydroxy Carboxylic Acid Surrogates

Heterocycles play an essential role in medicinal as well as in organic synthetic chemistry. The synthesis of these valuable scaffolds is an emerging and challenging field of today‘s research in organic chemistry. In recent years, several heterocycles as new synthons have emerged as potential nucleophiles in asymmetric transformations. Among them, 5H-oxazol-4-one is one of the strategic synthons for synthesizing enantioenriched α-alkyl-α-hydroxycarboxylic acid derivatives, which are otherwise very challenging via direct installation of a hydroxy group at the α-position of carbonyls. Over the years, considerable progress has been made to establish new and efficient methodologies under mild reaction conditions exploiting metal- and organo-catalysis. This review presents a comprehensive summary of various catalytic development in asymmetric synthesis employing 5H-oxazol-4-ones as α-alkyl-α-hydroxycarboxylic acid surrogates. (Figure presented.).