Ultrasound promoted Barbier reactions and Csp3–Csp2 Stille coupling for the synthesis of diarylmethanes and substituted benzophenones

Abstract

Here we present the preparation of a variety of diarylmethanes obtained via ultrasound Stille coupling under palladium catalysis between some substituted aryl compounds and benzyltributyltin compounds generated through sonicated Barbier reaction in a very short time reaction and excellent yield. The study reported below compares different methods to optimize the synthesis of usually unstable benzyltin derivatives and is another contribution to the investigation of Csp(3)-Csp(2) coupling process involving benzyl-aryl reagents. Substituted carboxylated benzophenones were easily prepared in a very good yield by oxidation of some diarylmethanes.

The Aqueous Barbier Polycondensation of Biomass‐Derived 5‐Chloromethylfurfural: A Proof of Concept Study to Access Functional Polymers

“…However, under this condition, slightly higher polymer molecular weight distribution was obtained. The sonochemical methods are commonly employed in Barbier reactions in which the sonication promotes electron transfer from metals . A presonicated reaction sample, however, resulted a negligible change in polymerization compared with the nontreated one.…”

Synthesis of Benzyl Ketones through Indium-Mediated Solvent-Free Reaction of Acid Chlorides with Benzyltins under Ultrasound Irradiation

“…Benzyltins 1,4-6 were synthesized from corresponding tin chlorides by Barbiertype sonicated reaction according to the literature procedures. 6 Reactions were monitored by thin-layer chromatography carried out on silica gel plates (60F-254) and visualized under UV light or using 5% phosphomolybdic acid in ethanol. External sonication was carried out using an ultrasonic probe (from Cole-Parmer 4710 series ultrasonic homogenizer of 20 kHz and 375 W) equipped with a 10 mm diameter titanium horn, which was immersed in an oil bath.…”

“…In this respect, we have established that this metal is a promoter of the mild, neutral and solvent-free reaction of acid chlorides with arylstannanes applied to the synthesis of hindered benzophenones 4 and alkyl aryl ketones under ultrasound irradiation. 5 Taking into account that, benzylstannanes are readily available and versatile precursors for the introduction of a variety of functional groups, 6 we now report an extension of our indium-mediated methodology directed towards the synthesis of benzyl ketones. A mechanism is proposed to explain the experimental results obtained.…”

The use of ultrasound in the South Cone region. Advances in organic and inorganic synthesis and in analytical methods

“…In Argentina, Ocampo et al . at Universidad Nacional del Sur [36] , presented the synthesis of a set of diarylmethanes ( 95 ) via ultrasound-assisted Stille coupling ( Scheme 25 ). The reaction preceded under Pd catalysis between benzyltributyltin compounds ( 93 ) and substituted aryl bromide or iodide ( 94 ).…”