Pages 11193?11194. In our follow-up studies exploring the reactivity of diisopropyl iminomalonates with hard C-nucleophiles (e.g., Grignard reagents, alkyl- and aryllithiums), we also attempted the addition of an acetophenone-derived lithium enolate (i.e., a soft C-nucleophile). We initially assigned a 6- membered lactone core for compound 68 based on routine NMR spectra; however, additional NMR studies strongly pointed to the presence of a 5-membered lactone scaffold (Figure 7A; panels B?D in the originally published figure are unchanged). As a result, we concluded that the enolate selectively added to the carbon atom of the iminomalonate C?N moiety. This switch of chemoselectivity (i.e., predominant N-attack versus exclusive C-attack of the iminomalonate C?N bond) appears to depend on the nature of the C-nucleophile (i.e., hard vs soft). Based on this new insight, we think it is reasonable to propose that during aziridine formation the ?-haloester (62)- derived enolate first performs a selective C-attack of the C?N moiety to afford intermediate 63. The original conclusions of the Article are unaffected by the structural revision of compound 68. We deeply regret this error in the initial structural assignment.