Phosphine-catalyzed [4+1] annulation of electron-deficient 1,3-dienes or 1,3-azadienes with maleimides has been successfully developed under very mild conditions, providing a convenient and highly efficient method for constructing 2-azaspiro[4.4]nonenes and 1,7-diazaspiro[4.4]nonenes. This reaction represents the first example of [4+1] cyclization between electron-deficient 4π-conjugated systems and non-allylic phosphorus ylides.

This paper describes a catalytic asymmetric Staudinger–aza-Wittig reaction of (o-azidoaryl)­malonates, allowing access to chiral quaternary oxindoles through phosphine oxide catalysis. We designed a novel HypPhos oxide catalyst to enable the desymmetrizing Staudinger–aza-Wittig reaction through the PIII/PVO redox cycle in the presence of a silane reductant and an IrI-based Lewis acid. The reaction occurs under mild conditions, with good functional group tolerance, a wide substrate scope, and excellent enantioselectivity. Density functional theory revealed that the enantioselectivity in the desymmetrizing reaction arose from the cooperative effects of the IrI species and the HypPhos catalyst. The utility of this methodology is demonstrated by the (formal) syntheses of seven alkaloid targets: (−)-gliocladin C, (−)-coerulescine, (−)-horsfiline, (+)-deoxyeseroline, (+)-esermethole, (+)-physostigmine, and (+)-physovenine.

Chiral 3-hydroxyoxindoles are biologically important molecular motifs which frequently present in natural products and artificial compounds. Herein, we report an ultraviolet light-driven asymmetric vinylogous aldol reaction between versatile isatins and...

A visible light-driven [3+3] annulation reaction of 2H-azirines with in situ generated Huisgen zwitterions from azodicarboxylates and phosphines is herein described. Under very mild conditions and irradiation of blue LED...