(BeDABCO)₂Pd₂Cl₆ as an efficient homogeneous catalyst for copper‐free Sonogashira cross‐coupling reaction

Abstract

An efficient catalytic system using 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride and palladium chloride ((BeDABCO) 2 Pd 2 Cl 6 ) was developed for the Sonogashira reaction. In the presence of a catalytic amount of this efficient, stable homogeneous catalytic system that is non-sensitive to air and moisture, various aryl halides were efficiently coupled with phenylacetylene in good yields in H 2 O at 50°C under copper-free conditions. Benzyl dabco as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species.

A versatile method for the synthesis of diaryl and alkyl aryl ketones via palladium‐catalysed cross‐coupling reaction of arylboronic acids with acyl chlorides

“…In continuation of our recent investigations on the synthesis and applications of the palladium complex of 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride with palladium chloride ((BeDABCO) 2 Pd 2 Cl 6 ), [41][42][43][44] we now report the extension of this complex as an efficient and highly active homogeneous catalyst for the cross-coupling reaction of various acyl chlorides with phenylboronic acid under phosphine-free conditions (Scheme 1).…”

Copper(i) catalyzed Sonogashira reactions promoted by monobenzyl nicotinium chloride, a N-donor quaternary ammonium salt

“…30 We have also reported the catalytic activity of Cu 4 Cl 5 species in combination with 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride (N-benzyl DABCO chloride) in Sonogashira coupling reactions. 27 In continuation of our recent studies on the development of catalytic systems containing quaternary ammonium and phosphonium salts, 17,[25][26][27] herein, we report the new catalytic system [MBNT] + [Cu 4 Cl 5 ] À as an effective catalyst for palladium free Sonogashira cross-coupling reactions. To date, only a few reports are available for the preparation and catalytic investigation of copper(I) complexes containing ammonium salts and Cu 4 Cl 5 .…”

“…High catalytic activity and selectivity are important parameters for these copper-assisted catalytic systems. Various ligands, such as triphenylphosphine, 20 1,10phenanthroline, 21 ethylenediamine, 22 N,N-dimethylglycine, 23 1,4-diazabicyclo[2.2.2]-octane (DABCO), 24,25 choline chloride, 26 N-benzyl DABCO, 27 have been investigated for this reaction system. Recently, we have used dibenzyl nicotinium chloride as the promoter in palladium-catalyzed C-C and C-S coupling reactions.…”