Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al₂O₃ under inspection

• Franziska Bernhardt,
• Ronald Trotzki,
• Tony Szuppa,
• Achim Stolle and
• Bernd Ondruschka

Beilstein J. Org. Chem. 2010, 6, No. 7, doi:10.3762/bjoc.6.7

• applied in solvent-free Pd-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl bromides with phenylboronic acid, and the performances of the individual SRS were compared [33][34][36][37][38][39][40][41][42]. Results and Discussion Incorporation of KF–Al2O3 as a basic component in organic synthesis

• pH measurements of aqueous suspension of the pure aluminas. Investigating the influence of different SRS, the Pd(OAc)2-assisted Suzuki–Miyaura coupling of phenylboronic acid (1) with different aryl bromides 2 furnishing p-substituted biphenyls 3 (Scheme 1) was chosen. Reactions were performed in a

• ][39][40][41][42][57][58]. The yield of the coupling product depends on the reactivity of the aryl bromide and the reverse basicity of the SRS used. SRS1 (neutral γ-Al2O3) yielded the best results with the tested aryl bromides, followed by basic SRS2 (α-Al2O3) and SRS3 (γ-Al2O3). The preference of

Polyionic polymers – heterogeneous media for metal nanoparticles as catalyst in Suzuki–Miyaura and Heck–Mizoroki reactions under flow conditions

• Klaas Mennecke and
• Andreas Kirschning

Beilstein J. Org. Chem. 2009, 5, No. 21, doi:10.3762/bjoc.5.21

• following. Under these optimized conditions several examples of successful cross coupling reactions were achieved that are listed in Table 1. We included combinations of electron rich and electron deficient aryl bromides with functionalized boronic acids and yields of coupling products were commonly good to

• ] these clusters exert pronounced catalytic activity in solution at very low concentrations. This view is further supported by the fact that the catalytic species operating in the present case is able to promote Suzuki–Miyaura cross coupling reactions with aryl bromides while aryl chlorides are not good

• substrates under these standard conditions. This observation has been noted in many examples of heterogenized palladium salts or complexes [34]. Likewise, these species are commonly not reactive enough to promote the Heck–Mizoroki reaction with aryl bromides. It should be noted that under supercritical or

A convenient catalyst system for microwave accelerated cross- coupling of a range of aryl boronic acids with aryl chlorides

• Matthew L. Clarke,
• Marcia B. France,
• Jose A. Fuentes,
• Edward J. Milton and
• Geoffrey J. Roff

Beilstein J. Org. Chem. 2007, 3, No. 18, doi:10.1186/1860-5397-3-18

• biaryl synthesis and is widely applied in organic chemistry. [1][2][3][4][5][6] In the last 10 years, there has been intense research interest in Suzuki reactions of aryl chloride substrates since these substrates are cheaper and more widely available than aryl bromides. A range of catalysts now exist