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

Abstract

Pd‐catalyzed Negishi cross‐coupling reactions between organozinc compounds and (hetero)aryl bromides have been reported when using bulk water as the reaction medium in the presence of NaCl or the biodegradable choline chloride/urea eutectic mixture. Both C(sp3)‐C(sp2) and C(sp2)‐C(sp2) couplings have been found to proceed smoothly, with high chemoselectivity, under mild conditions (room temperature or 60 °C) in air, and in competition with protonolysis. Additional benefits include very short reaction times (20 s), good to excellent yields (up to 98 %), wide substrate scope, and the tolerance of a variety of functional groups. The proposed novel protocol is scalable, and the practicability of the method is further highlighted by an easy recycling of both the catalyst and the eutectic mixture or water.

Deep Eutectic Solvents in Solar Energy Technologies

“…All of these exceptional features, combined with the low cost of components, easiness of preparation with high purity, high biodegradability and low toxicity, have made DESs attractive and promising as a new generation of nonaqueous solvents/cosolvents for a broad range of applications in organic synthesis [ 24 , 25 , 26 ], main group chemistry [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], metal-, bio-, and organo-catalysis [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ], dissolution and extraction processes [ 54 , 55 , 56 , 57 , 58 ], electrochemistry [ 59 , 60 ], material chemistry [ 61 , 62 ], photosynthesis [ 63 ], and even protein crystallization [ 64 ].…”

(Phenylseleno)acetic acid based precursor for the regiospecific synthesis of 1-phenylseleno-2-alkanones*

“…Powdered tetrakis(triphenylphosphine)palladium(0) (0.15 mmol) was added to a solution of the acyl chloride 3 (1 mmol) in 15 mL of tetrahydrofuran at 0−5 °C and under argon. Then a solution of nbutylzinc chloride [9] (1.3 mmol) was added slowly along the side of the reaction flask by using a syringe pump over 1.5 h with vigorous stirring. The dark solution was allowed to reach room temperature gradually and then stirred at this temperature for 4 h. A saturated aqueous sodium hydrogen carbonate solution (1.5 mL) was added, and the slurry was filtered through a Celite pad, dried over sodium sulfate, filtered, and evaporated.…”

Advancing Air‐ and Moisture‐Compatible s‐Block Organometallic Chemistry Using Sustainable Solvents

“…More recently, the same group has extended the use of the NaCl/water combination or the eutectic mixture 1ChCl/2Urea as sustainable reaction media to the Pdcatalysed Negishi coupling of organozinc reagents (ZnR 2 ) with aryl(heteroaryl) halides, working at room temperature or 60°C and in the presence of air. [58]…”