Fast Suzuki–Miyaura cross-coupling reaction catalyzed by the Na2Pd2Cl6 complex with ethyl calix[4]aryl acetate at room temperature in aqueous medium under ligand-free and ambient atmosphere

Visible-Light-Promoted, Catalyst-Free Gomberg–Bachmann Reaction: Synthesis of Biaryls

“…The reaction mixture was stirred and irradiated by 4 W blue LEDs (460 nm) at room temperature under an Ar atmosphere for 18 h. The reaction mixture was purified by flash chromatography using 10% EtOAc/hexane to afford 74 mg (56% yield, o/m/p = 2.2:1.3:1) of product as a yellow oil: 1 H NMR (400 MHz, CDCl 3 ) δ 7.53−7.42 (m, 3H), 7.41−7.33 (m, 4H), 7.32−7.23 (m, 9H), 7.19 (d, J = 1.7 Hz, 1H), 7.17 (d, J = 1.7 Hz, 1H), 7.03−6.99 (m, 3H), 6.98−6.95 (m, 3H), 3.81 (s, 3H), 3.80 (s, 3H), 3.78 (s, 3H); 13 n-Chloro-3′-methoxy-1,1′-biphenyl (3ac). 15 The compound was prepared according to general procedure A using chlorobenzene and 3-methoxybenzene diazonium tetrafluoroborate. The reaction mixture was stirred and irradiated by 5 W white LEDs (430−660 nm) at room temperature under an Ar atmosphere for 18 h. The reaction mixture was purified by flash chromatography using 10% EtOAc/hexane to afford 88 mg (67% yield, o/m/p = 3.2:1.2:1) of product as a yellow oil: 1 n-Chloro-4′-methyl-1,1′-biphenyl (3ad).…”

Evaluation of Nitrogen-Based Polymeric Heterogeneous Catalysts for the Suzuki–Miyaura Cross-Coupling Reaction in Water

“…First, phase transfer reagents can be used to dissolve the nonpolar substrates and increase their concentrations in the reaction medium. Phase transfer catalysts or surfactants, such as calix­[ n ]­arenes, sodium dodecyl sulfate, tetrabutylammonium bromide, and polyethylene-tagged compounds, have already been widely studied to improve the catalytic performance. − The second way to enhance the catalytic performance of the Suzuki–Miyaura cross-coupling reaction in water is to use a heterogeneous catalyst containing hydrophilic ligands. Among the variety of ligands possessing lone pairs of electrons that are capable of coordinating with noble metals, one of the most widely studied groups of hydrophilic ligands are phosphine ligands.…”