The 4-isothiocyanatopyrazolones were exploited as a class of efficient synthons for the construction of triazoline derivatives via asymmetric [3+2] annulation with azodicarboxylates, providing a wide range of structurally diverse multi-nitrogen-containing spirocycles in excellent yields (up to 97%) with excellent enantioselectivities (up to 97% ee).
Key words
asymmetric catalysis - isothiocyanatopyrazolones - triazolines - annulation - enantioselectivity