Metal-free N-H insertions of donor/acceptor carbenes.

Synthetically useful transformations arise from the thermal decomposition of aryldiazoacetates in the presence of primary and secondary amines without the use of a metal catalyst. Thermally generated, free donor/acceptor carbenes directly undergo N-H insertion with amines through selective aza-ylide formation to afford a variety of α-amino esters in 53-96% yields.