Metal-Free Insertion Reactions of Diazo Carbonyls to Azlactones.
Amanda C de MelloPatrícia B MomoAntonio Carlos Bender BurtolosoGiovanni Wilson AmarantePublished in: The Journal of organic chemistry (2018)
Insertion reactions of diazo carbonyls to azlactones in basic conditions have been performed. The developed method allows the preparation of a wide range of oxazole derivatives in yields ranging from 74 to 98%. Different substituents on both azlactone rings and diazo carbonyls do not compromise the methodology, even those containing stereogenic centers. Isotopic labeling experiments revealed the mechanism may proceed through a rare diazo carbonyl activation by an ammonium salt derivative.
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