Ligand‐Free Suzuki–Miyaura Cross‐Coupling Reactions in Deep Eutectic Solvents: Synthesis of Benzodithiophene Derivatives and Study of their Optical and Electrochemical Performance

Abstract

Dedicated to Professor Franco Cozzi on the occasion of his 70th birthday.

Advances in deep eutectic solvents and water: applications in metal- and biocatalyzed processes, in the synthesis of APIs, and other biologically active compounds

“…32 The same ligand-free approach has been then applied to promote smooth SM coupling reactions, under aerobic conditions, between dihalogeno-substituted benzodithiophenes (BDTs) and aryl-, alkenyl-and alkynyltrifluoroborate salts in a ChCl/ Gly eutectic mixture to synthesize valuable π-conjugated BDT adducts in up to 79% yield, whose optical and electrochemical properties have been deeply investigated by means of absorption and cyclic voltammetry measurements. 33 The use of potassium aryltrifluoroborates in pure water was less effective. In 2015, Schatz and co-workers described an efficient, broadly applicable and sustainable SM protocol in pure water with a Pd loading as low as 0.4 mol%, without any ligand or organic co-solvent, working with a range of activated and nonactivated aryl halides (Scheme 2).…”

Sustainable Pd-Catalyzed Direct Arylation of Thienyl Derivatives with (Hetero)aromatic Bromides under Air in Deep Eutectic Solvents

“…Furthermore, taking advantage of some peculiar properties like high viscosity, conductivity, and polarity, as well as high solubility in water, which usually simplify the isolation of the final products, DESs have been successfully employed as alternatives to VOCs in many organic and organometallic transformations. − For example, the employment of polar organometallic reagents like alkyl- and aryllithium species , in DESs has been successfully proven under mild conditions and very short reaction times. A very important class of transformations that were positively affected by the use of DESs consist of cross-coupling reactions, as reported for Suzuki–Miyaura, − Sonogashira, ,, Hiyama, , Negishi, Stille–Migita, and Ullmann-type − reactions, which have been extensively investigated in recent years.…”

Scalable Negishi Coupling between Organozinc Compounds and (Hetero)Aryl Bromides under Aerobic Conditions when using Bulk Water or Deep Eutectic Solvents with no Additional Ligands

“…As part of our ongoing research in DES and water chemistry, we recently reshaped some transition metal‐catalyzed cross‐coupling reactions, like the Suzuki–Miyaura, [12a,b] the Sonogashira, [12c] and the Ullmann‐Goldberg couplings, [12d,e] and the aminocarbonylation of aryl iodides [12f] in bioinspired eutectic mixtures, and set up the direct Pd‐catalyzed cross‐coupling between organolithiums and (hetero)aryl halides, by using bulk water as a non‐innocent reaction medium in the presence of NaCl as a cheap additive [12g] . Herein, we report the Pd‐catalyzed NC between (hetero)aryl bromides and organozinc halides, and compare the outcome of the reactions both in DESs and in water/NaCl.…”