A facile and efficient approach for the synthesis of spirooxindoles has been developed via the coupling of spirocyclic C, C-palladacycles with CH2Br2. The key spirocyclic palladacycles are generated catalytically via intramolecular remote C–H activation. A range of spirooxindoles can be synthesized in good to excellent yields from readily available starting materials.
Pd-Catalyzed Highly Regio- and Stereoselective Formation of C–C Double Bonds: An Efficient Method for the Synthesis of Benzofuran-, Dihydrobenzofuran-, and Indoline-Containing Alkenes
A highly regio- and stereoselective C–C double bond formation reactionvia Pd-catalyzed Heck-type cascade process with N-tosylhydrazones has been developed. Various N-tosylhydrazones derived from both ketones and aldehydes are found to be efficient substrates to provide di- and trisubstitutedolefins with high regio- and stereoselectivity. Furthermore, this reaction has a good functional group tolerance
spirocyclization forming spirooxindoles and spirodihydrobenzofurans has been achieved. Mechanistic studies suggest that the transformation proceeds through sequential carbopalladation, C–Hactivation, and benzyne insertion. Both classes of spirocycles have been synthesized in good to excellent yields, and the procedure is readily scalable.
This Letter describes a Pd-catalyzed Tsuji–Trost-type/Heck reaction with allyloxy-tethered aryliodides and aziridines. The strategy provides efficient access to benzannulated medium-sized rings via intermolecular cyclization. The substrate aryliodide has two oxidative addition sites, that is, the aromatic C–I bond and the allyl–oxygen bond. The chemoselective oxidative addition of allyl–oxygen bonds
Sonogashira-type cross-couplings are one of the most significant alkynylations in organic chemistry. One of the first palladium-catalyzed intramolecular Heck/Sonogashira reactions of alkenes with terminal alkynes is now reported. With this method, a variety of uniquely substituted chiral benzene-fused heterocycles bearing a propargyl-substituted all-carbon quaternary stereocenter were obtained in a