Enantioselective [3 + 2] annulation of 4-isothiocyanato pyrazolones and alkynyl ketones under organocatalysis
Wenyao Wang, Shiqiang Wei, Xiaoze Bao, Shah Nawaz, Jingping Qü, Baomin Wang
Abstract
An asymmetric [3 + 2] annulation reaction of 4-isothiocyanato pyrazolones with alkynyl ketones in the presence of an organic catalyst derived from a cinchona alkaloid under mild conditions is realized. This protocol provides unprecedented expeditious access to a wide range of optically active spiro[pyrroline-pyrazolones] with various electronic properties in high yields with good to excellent enantioselectivities.
Topics & Concepts
PyrazolonesAnnulationEnantioselective synthesisOrganocatalysisChemistryCatalysisOrganic chemistryStereochemistryCatalytic C–H Functionalization MethodsSulfur-Based Synthesis TechniquesSynthesis and Catalytic Reactions