Asymmetric [3+2] spiroannulation of pyrazolone-derived Morita–Baylis–Hillman carbonates with alkynyl ketones: facile access to spiro[cyclopentadiene-pyrazolone] scaffolds

An organocatalyzed asymmetric [3+2] spiroannulation reaction of pyrazolone-derived MBH carbonates with alkynyl ketones was described, affording chiral spiro[cyclopentadiene-pyrazolone] scaffolds in good yields with high degrees of enantiocontrol.