No abstract

A gold rush can occur not only among diggers at the banks of a remote river, but also among chemists in catalytic research laboratories. Gold salts displaying high catalytic activity facilitate domino coupling reactions in C−heteroatom and C−C coupling. Thus, for example, furyl‐substituted products 2 are preparatively accessible in one step from three units of allenyl ketone 1.

C-C coupling by transition metal catalyzed C-H activation has developed into a diverse area of research. The applicable catalysts are manifold, and the variety of products obtained range from basic chemicals to pharmaceuticals and building blocks for carbon networks. One reaction, in which several C-C bonds are formed under C-H activation of a methyl group, is the conversion of ortho-iodoanisole according to Equation (1).

for carrying out the "B NMR measurement. 2 crystallized in the form of dark red. very small octahedral crystals which contained half a molecule of ether per formula unit. The systematic absences -h + k + l = 3n for (h,k,f) and I = 6n for (001) and the number of the formula units to be expected led to the rhombohedra1 space group R%(D3d/6). The lattice constants were refined on the basis of 18

Cyclopentadiene and metallocenes, typically zirconocene dichloride, are suitable substrates for multiple arylations with aryl bromides in palladium-catalyzed reactions. Thus, various aryl bromides bearing either an electron-donating or an electron-withdrawing substituent can react with these substrates to afford the corresponding 1,2,3,4,5-pentaaryl-1,3-cyclopentadienes in a single preparative step. Derivatives of cyclopentadiene, including di- and trisubstituted cyclopentadienes, and indene are arylated in a similar fashion.