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

Abstract

This work reports Xantphos‐coordinated palladium dithiolate complexes as catalysts for decarboxylative Sonogashira coupling reaction of phenyl propiolic acid and 2‐butynoic acid with various iodoarenes. These palladium aryl dithiolate complexes were synthesized and characterized by 1H and 31P nuclear magnetic resonance (NMR) spectroscopy, melting point, and elemental analysis (CHNS). Synthetic utility for the reported protocol is explored for the effect of various functional groups on the yield of corresponding heteroaryl alkynes. The current protocol showed excellent catalytic activity towards decarboxylative alkynylation reaction with high turn‐over number (TON) up to 105 and turn‐over frequency (TOF) up to 104 h−1. The catalyst could be recycled up to six recycles without losing its catalytic activity. The in situ generation of palladium nanoparticles (PdNPs) was observed after the third recycle, and the amount was significant after the sixth recycle, which were confirmed and characterized by powder X‐ray diffraction (XRD), scanning electron microscope (SEM), and energy‐dispersive X‐ray (EDX) analysis and high‐resolution transmission electron microscopy (HR‐TEM). The catalytic activity of the reaction is attributed to the formation of PdNPs.

Cu-Mediated Tandem 2,3-Disubstituted Indole Synthesis from Simple Anilines and Internal Alkynes via C–H Annulation

“…All of the chemicals and solvents were procured with high purities from Sigma-Aldrich, Alfa Aesar, etc., and used without further purification. All diphenylacetylene derivatives are known compounds and were synthesized using the reported methods . The reactions were carried out in 10 mL reaction vials containing a stir bar with sealed aluminous headspace caps.…”

Organosulphur and organoselenium compounds as ligands for catalytic systems in the Sonogashira coupling

“…The system is commercially accessible. 99 L29 is a thiourea-based ligand. 100 It is synthesized (Scheme 18) in a single-pot reaction.…”

“…Aryl bromides are not converted significantly into the product in the presence of this catalyst. 99 Complex 26 works for catalyzing the reaction (Scheme 60) between phenylacetylene and 4-bromoacetophenone. 100 Nearly 76% conversion is achieved within 6 hours in the presence of 1.0 mmol of this complex at 100 °C.…”

Recent Expedition inPd‐CatalyzedSonogashira Coupling and Related Processes†

“…Xantphos ‐coordinated Pd complexes of dithiolate ligands were designed for the decarboxylative Sonogashira coupling with activated aryl iodides and bromides in 2021 (Scheme 24). [ 137 ]…”