A Stable, Convertible Isonitrile as a Formic Acid Carbanion [^-COOH]
Equivalent and Its Application in Multicomponent Reactions

Kreye Oliver. Westermann Bernhard. Wessjohann LudgerA.. Synlett  2007,  3788-3192 

After this paper had been published the authors realized that another recent literature related to the published paper should have been cited: Vamos, M.; Ozboya, K.; Kobayashi, Y. ‘Synthesis of Bicyclic Pyroglutamic Acid Featuring the Ugi Reaction and the Unique Stereoisomerization at the Ring Juncture by Grob Fragmentation followed by Transannular Ketene [2+2] Cycloaddition Reaction’ Synlett 2007, 1595-1599.The authors apologize for not citing this work.