Synthesis of 1,2-Disubstituted C-Aryl Glycosides via Palladium/Norbornene Cooperative Catalysis.

The Catellani reaction offers an opportunity to address multiple chemical bonds in a single pot. However, it is still quite a challenge to construct fully substituted olefins via this strategy, especially in electron-rich, unstable, and highly functionalized glycals. Herein we report the first palladium-catalyzed Catellani reaction for the direct preparation of 1,2-disubstituted C-aryl glycosides from easily available 2-iodoglycals, bromoaryl, and alkene/alkyne substrates.

Furan Dearomatization: A Route to Diverse Fluoroalkyl/Aryl Triazoles.

The 5-fluoroalkyl-1,2,3-triazoles, serving as a pivotal element in medicinal chemistry, hold substantial research significance. In this work, we developed a furan dearomatization reaction for the synthesis of various 5-fluoroalkyl-1,2,3-triazoles, which contains -CF, -CFH, -CFCF, -CFCFCF, -CFCOEt, and -CF. This methodology relies on the intermolecular [3 + 2] cycloaddition/furan ring-opening triggered by α-fluoroalkyl furfuryl cation with azides to stereoselectively synthesize a series of ()-fluoroalkyl enone triazoles.

Diphosphine Ligand-Enabled Nickel-Catalyzed Chelate-Assisted Inner-Selective Migratory Hydroarylation of Alkenes.

The precise control of the regioselectivity in the transition metal-catalyzed migratory hydrofunctionalization of alkenes remains a big challenge. With a transient ketimine directing group, the nickel-catalyzed migratory β-selective hydroarylation and hydroalkenylation of alkenyl ketones has been realized with aryl boronic acids using alkyl halide as the mild hydride source for the first time. The key to this success is the use of a diphosphine ligand, which is capable of the generation of a Ni(II)-H species in the presence of alkyl bromide, and enabling the efficient migratory insertion of alkene into Ni(II)-H species and the sequent rapid chain walking process.

SPSiPs, a Class of Diphosphine Ligands Based on SPSiOL with a Large Dihedral Angle.

The development and the synthetic applications of a novel class of diphosphine ligands (SPSiPs) based on chiral spirosilabiindane diol (SPSiOL) are presented. Starting from SPSiOL, the diphosphine ligands could be readily prepared in three steps with high efficiency. This novel class of diphosphine ligands features rigid configuration, a large dihedral angle, a large P-M-P angle, and a long P-P distance.

Dual Roles of Azide: Dearomative Dimerization of Furfuryl Azides.

A dearomative dimerization of furfuryl azides for the construction of furfuryl triazoles is developed. As a rare leaving group, azide is capable of initiating the generation of a furfuryl cation under the Lewis acid-catalyzed conditions, followed by reacting with the other azide to realize an intermolecular [3 + 2] cycloaddition/furan ring-opening cascade. By extending the reaction time, a fragmentation reaction of resulting furfuryl triazoles occurs to afford 1-triazoles in high yield.