Carboxylic Acid-Enabled Vinylene Transfer Reaction by Co(III) Catalyst: Scope and Applications to the Five-Step Total Synthesis of Protoberberine Alkaloids Containing Free Hydroxyl Group without Protection.

A Co(III)-catalyzed vinylene transfer reaction enabled by carboxylic acid is presented. This redox-neutral transformation tolerates various functional groups, including free hydroxyl groups, and features practicality. Five-step routes based on the vinylene transfer reaction and Heck annulation have been devised to the total synthesis of 8-oxodehydrodiscretamine and 2-demethyl-oxypalmatine without the protection of the free hydroxyl functionality.

In Situ Generation of Propadiene from 1-Cyclopropyl-1-nitrosourea for Rh(III)-Catalyzed Synthesis of Isoquinolinones and Pyridinones Containing a Methylene Functionality.

A Rh(III)-catalyzed synthesis of isoquinolinones and pyridinones bearing a methylene motif is presented. This protocol using easily accessible 1-cyclopropyl-1-nitrosourea as the precursor of propadiene features simple and practical manipulation and tolerates a broad spectrum of functional groups, including strong coordinating N-containing heterocyclic substituents. Late stage diversification and the rich reactivity of methylene for further derivations demonstrate the value of this work.

Rh(III)-Catalyzed Synthesis of Amino-isocoumarins with N-Functionalized Cyclic Carbonates via C-H/O-H Annulation.

A practical method to access amino-isocoumarins catalyzed by a Rh(III) complex through redox-neutral C-H/O-H annulation has been disclosed. The use of N-functionalized cyclic carbonates is crucial to facilitate the catalytic turnover, and a broad spectrum of amino-isocoumarin derivatives were prepared with satisfactory yields. Amino-isocoumarin estrone conjugated with a selenocyano functionality was identified to be nearly four times as active as the marketed drug abiraterone against T47D cancer cells.