Role of copper chlorides in the Sandmeyer and Meerwein reactions

The Cu(i) catalyzed Meerwein reaction in aqueous solutions proceeds via a radical mechanism. The effect of several ligands

“…These results were expected on the basis of previous reports on the Meerwein reaction. 1,[14][15][16] It should be noted that in solutions containing Cu(I) ions and fumaric acid two main Cu(I) species are present: the Cu I (fum) complex and Cu + aq . The concentration of each of these species can be calculated from [Cu + ] total and [fum] or the absorbance of Cu I (fum) according to a previously reported method.…”

“…Cu(I) complexes are important catalysts in various industrial processes, e.g. the Sandmeyer reaction, [1][2][3][4] the Ullmann reaction, [4][5][6][7] the click reactions, 4,[8][9][10][11][12][13] and the Meerwein reaction. 1,4,[14][15][16][17] In aqueous solutions ligands are required to stabilize Cu I aq , due to the low solubility of Cu 2 O and its disproportionation reaction.…”

“…the Sandmeyer reaction, [1][2][3][4] the Ullmann reaction, [4][5][6][7] the click reactions, 4,[8][9][10][11][12][13] and the Meerwein reaction. 1,4,[14][15][16][17] In aqueous solutions ligands are required to stabilize Cu I aq , due to the low solubility of Cu 2 O and its disproportionation reaction. 4,18 These ligands affect the redox potential of the central copper ion and often impose steric constraints which affect the catalytic properties of the Cu(I) complex.…”

“…The Meerwein reaction, reaction (1), is often carried out in alkenes [14][15][16][17] though the latter are known Cu(I) ligands 19 that decrease the reduction potential of the Cu(I) ion, thus decreasing its catalytic properties. 20,21 The detailed mechanism of the Meerwein reaction is still not fully known.…”

“…Some studies suggest that the first step is the formation of a π bond between the copper and the alkene forming a transient product that activates the double bond. 1 ArN…”