Bisphosphine catalyzed sequential [3 + 2] cycloaddition and Michael addition of ynones with benzylidenepyrazolones via dual α′,α′-C(sp3)-H bifunctionalization to construct cyclopentanone-fused spiro-pyrazolonesDedicated to 100th anniversary of Nankai University.Electronic supplementary information (ESI) available. CCDC 1540162 and 1567473. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8ob02675k

A bisphosphine-catalyzed sequential [3 + 2] cycloaddition and Michael addition reaction of ynones with benzylidenepyrazolones has been developed. Under the catalysis of DPPB [1,4-bis(diphenylphosphino)butane], the reaction proceeded smoothly to give spiro-[cyclopentanone] pyrazolone derivatives in moderate to good yields with good diastereoselectivities via sequential dual α′,α′-C(sp 3 )-H bifunctionalization annulation. This strategy provides a novel route toward the synthesis of spiro-[cyclopentanone] pyrazolones containing three contiguous stereocenters which possess potential pharmaceutical activities. A sequential [3 + 2] cycloaddition and Michael addition reaction of ynones with benzylidenepyrazolones afforded cyclopentanone-fused spiro-pyrazolones catalyzed by DPPB via dual α′,α′-C(sp 3 )-H bifunctionalization.