“…[11] It is remarkable that isothiocyanates 7 and carbon disulfide 8 react with azides 1 at room temperature, whereas aldehydes, being more reactive carbonylc ompounds, requireh eating. [15] In the discussed reaction, the intramolecular proton transfer (see Scheme 5) ensures the aforementioned polarization as well as increasing the nucleophilicity of the malonate moiety. For intermediate 10,t his is ad isfavored 5-endo-trig process, whereas for the corresponding intermediates in the PPh 3 -initiated reactiono f1 with isothiocyanates 7 or carbon disulfide 8, Scheme5.Proposed mechanism for the formationo fpyrrolidines 2. the rate-limiting step is af avored 5-exo-trig cyclization.…”