Nickel- and Palladium-Catalyzed Cross-Coupling of Stibines with Organic Halides: Site-Selective Sequential Reactions with Polyhalogenated Arenes

Abstract

Herein, we disclose a general and efficient method for the synthesis of Sb-aryl and Sb-alkyl stibines by the nickelcatalyzed cross-coupling of halostibines with organic halides. The synthesized Sb-aryl stibines couple with aryl halides to give biaryls efficiently via palladium catalysis. Sequential reactions of stibines with polyhalogenated arenes bearing active C−I/C−Br sites and inactive C−Cl sites successfully proceeded, resulting in the formation of a variety of complex molecules with good site selectivity. Drugs such as diflunisal and fenbufen, as well as a fenofibrate derivative, were synthesized on gram scales in good yields, together with the high recovery of chlorostibine. Furthermore, catalytic mechanisms are proposed based on the results of control experiments.

Adaptable Biomolecule-Interactive Dual Colorimetric Chemosensor for Cu2+ and Pd2+: Insight from Crystal Structure, Photophysical Investigations, Real-Time Sampling, and Molecular Logic Circuits

“…Though beneficial, the copper ion at an excessive concentration is very toxic for living organisms. Excess intake of it can trigger severe neurodegenerative diseases such as Alzheimer’s, Menke’s, Parkinson’s, and Wilson’s diseases as well as gastrointestinal issues like vomiting, headaches, weakness, and diarrhea. − In contrast, the precious platinum group metal (PGM) palladium is utilized extensively in a variety of fields, including the manufacturing of jewelry and navigational aids for aircraft and cars, as well as coating materials, fuel cells, chemical catalysts, dental crowns, and medical equipment. − Due to their distinctive catalytic reactivity, palladium complexes (zero or bivalent) have become essential organometallic catalysts in numerous coupling reactions, including Heck, Suzuki, Stille, Negishi, Sonogashira, and Kumada, which are frequently utilized for producing complicated molecules in the pharmaceutical sector. − Palladium’s nonbiodegradability, combined with its growing emission in the environment, has considerably raised the probability of palladium ingestion or internalization in living creatures via accumulation in the food chain. This situation raises a fearful health problem including severe primary skin and eye irritations because Pd 2+ ions are capable of binding strongly to a variety of biomolecules like DNA and proteins (different enzymes, silk fibroin, and casein) or different biomacromolecules (vitamin B6) and thiol-containing amino acids, which can interfere with enzymatic metabolisms and negatively impact organ functions. − Therefore, it is extremely important to develop techniques that enable the highly sensitive and selective detection of these metal pollutants, such as copper and palladium.…”

Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary Amines toward Functionalized Carbazoles

“…Recently, we obtained organostibines containing 5,6,7,12-tetrahydrodibenzo­[ c , f ]­[1,5]­azastibocines by nickel-catalyzed cross-coupling of halostibines with organoboronic acids . Due to the intramolecular interaction of Sb with N and the special N–Sb coordination bond, the synthesized organostibines mentioned above are not only excellent coupling partners with enhanced reactivity in transition-metal-catalyzed cross-coupling reactions , but also synthons in base-promoted synthesis of chalcogenated ( Z )-olefins and ethers (Scheme a) . We hypothesized that when 5,6,7,12-tetrahydrodibenzo­[ c , f ]­[1,5]­azastibocine-involved organostibines were used as ligands in Pd-catalyzed double N-arylation, the Sb could act as a donor (toward the Pd center) and an acceptor (toward the N atom) simultaneously.…”