Urea Activation of α-Nitrodiazoesters: An Organocatalytic Approach to N–H Insertion Reactions

The combination of a urea catalyst and an α-nitro-α-diazo
ester gives rise to a reactive species able to undergo insertion into
the N–H bonds of anilines. This new strategy to achieve N–H
insertion reactivity is in contrast to typical metal-catalyzed conditions
for the generation of carbenoids from α-diazocarbonyl compounds.
This report includes the extension of the insertion reaction to a
three-component coupling for the construction of α-amino-α-aryl
esters in high yield.