Fig. 3. Products from mode B three-component reactions. Trapping of zwitterions (cf.III) by (a) carbonyl electrophiles, (b) isocyanates, and (c) electron-deficient alkenes or alkynes. iA byproduct comprising two molecules of dimethyl acetylenedicarboxylate and one of quinoline was isolated (in ca. equal mass to that of 21, see ESI†). iiRelative configuration not assigned.
