LiHMDS-Promoted Palladium-Catalyzed Sonogashira Cross-Coupling of Aryl Fluorides with Terminal Alkynes

Abstract

A highly efficient Pd-catalyzed Sonogashira coupling of various aryl fluorides with terminal alkynes in the presence of LiHMDS was developed. Both unreactive electron-rich fluoroarenes and electron-poor fluoroarenes proceeded smoothly and afforded the corresponding internal alkynes in moderate to excellent yields.

Stereoselective Palladium‐Catalyzed C−F Bond Alkynylation of Tetrasubstituted gem‐Difluoroalkenes

“…We have direct evidence for the existence of complex B (X‐ray structure) and its reactivity downstream in the catalytic cycle. Next, complexation of terminal alkyne 2 to Pd centre leads to complex C . Increased acidity of acetylenic proton of alkyne 2 due to complexation allows deprotonation by a weak base (e.g., NEt 3 ), then ligand exchange with iodide (overall eliminating a molecule of HI) affords R‐Pd II ‐alkyne complex D .…”

Recent Advances in Transition‐metal‐catalyzed C−C Bond Formation via C(sp2)−F Bond Cleavage

“…As shown in Scheme 35, Zhao et al have described the Pd-catalyzed SÀ H reaction of aryl fluorides with terminal alkynes in the presence of LiHMDS. [44] The reaction proceeds effectively even in the absence of copper catalysts, ligands, and bases, and a variety of electron-rich and electron-deficient aryl fluorides become accessible as coupling partners. More importantly, catalyst system for this transformation can be utilized for aryl chlorides and bromides.…”

Xantphos‐coordinated palladium dithiolates: Highly efficient catalyst for decarboxylative Sonogashira reaction into corresponding alkynes

“…Substituted alkynes are fundamental structural motifs, which serve as versatile building blocks in the synthesis of pharmaceuticals, natural products, agrochemicals, and functional materials. [ 1,2 ] Over the past three decades, the Sonogashira cross‐coupling reaction plays the most efficient and reliable approach for Csp–Csp 2 bond formation in the synthesis of substituted alkynes. [ 3,4 ] Generally, the catalytic system for these reactions includes phosphine ligated palladium complexes and copper salts as cocatalyst with an excess amount of amine as a base or solvent.…”