Rapid Suzuki-Miyaura Couplings with ppm Level of Palladium Catalyst in a High-Pressure and High-Temperature Water System

Abstract

A microflow process was developed for Suzuki-Miyaura Couplings (SMCs) in high-pressure and high-temperature (HPHT) water with a small amount of ethanol. Using this approach, an efficient SMC between 4-methylphenylboronic acid and iodobenzene as a model reaction was demonstrated in water medium, in the presence of ppm order PdCl2/NaOH as a simple catalyst/base without any additional ligands, affording the desired products in good yields within <25 s of residence time. The strategy developed for SMCs also demonstrated an aspect of separation by quantitative tracing of 0.1 ppm contaminated Pd with the product, which might be attributed to the low catalyst amount along with the reaction conditions, as well as the immediate membrane separation applied in the sequence.

Scope and limitation of propylene carbonate as a sustainable solvent in the Suzuki–Miyaura reaction

“…That is the reaction time of compounds 5 and 7 with a fused and isolated aromatic ring, respectively, is very similar. There can be found several data in the literature, such as HPLC of phenylboronic acid 56 (6) and LC-MS data of 6-phenylpyridazin-3(2H)-one 57 (18a). No information is available, however, for our new products: 11b, 19b and 20b.…”

“…One explanation can be the inhomogenity of temperature in the oil bath, although the oil was wellstirred with a stirring bar. Product 12 [64][65][66] can be obtained from 2-iodopyridine (2) and phenylboronic acid (6) in approximately 65% average yield in the longest reaction (7 h, oil bath) and with 66% average yield in 1 h (MW heating). Note that the use of MW irradiation in Suzuki-Miyaura reaction allows us to save time and energy.…”

“…PC was used as prominently green solvent for the Suzuki-Miyaura cross coupling reaction. The reaction was examined with 3 different heterocyclic iodocompounds (2, 3, 4) with 4 different boronic acids (5,6,7,8) under microwave condition and conventional oil bath heating. In general, iodopyridines 2 and 3 reacted smoothly in the expected way providing the cross- coupled product.…”

“…4 At room temperature, the reaction takes place with low yield; therefore, the use of special catalyst might be required 5 or increased temperature and pressure are needed. 6 Several efforts were taken to carry out Suzuki-Miyaura and further cross coupling reactions under green and sustainable conditions. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] Reeves and co-workers studied the effects of propylene carbonate (PC) and various polar and nonpolar solvents on palladium-catalyzed Suzuki-Miyaura coupling of chloroaryl triates.…”

Pd(CH3CN)2Cl2/Pipecolinic Acid as a Highly Efficient Catalytic System for Suzuki-Miyaura Cross-coupling Reaction of Bromoaryl Carboxylic Acids in Water

“…However, 0.01-2 mol% of Pd(OAC) 2 /DABCO should be used to obtain a high yield in the coupling reaction of aryl bromides and phenylboronic acid. Recently, a ppm level of PdCl 2 has been developed for the Suzuki-Miyaura coupling reaction and in this process high-pressure and high-temperature water is necessary in order to gain a high yield [21]. Amino acid complexes show good catalytic performance in C-C bond and C-N formation [18][19][20]22,23].…”