1254105-11-7Relevant articles and documents
In Situ Generation of ArCu from CuF2 Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient
Delpozo, Juan,Casares, Juan A.,Espinet, Pablo
, p. 4274 - 4284 (2016)
A bimetallic system of Pd/CuF2, catalytic in Pd and stoichiometric in Cu, is very efficient and selective for the coupling of fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p-cyanophenyl, p-nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by CuII, followed by disproportionation and transmetalation from the CuI(aryl) to PdII, upon which coupling takes place. CuIII formed during disproportionation is reduced to CuI(aryl) by excess aryl silane, so that the CuF2 system is fully converted into CuI(aryl) and used in the coupling. Moreover, no extra source of fluoride is needed. Interesting size selectivity towards coupling is found in competitive reactions of hindered aryl silanes. Easily accessible [PdCl2(IDM)(AsPh3)] (IDM = 1,3-dimethylimidazol-2-ylidene) is by far the best catalyst, and the isolated products are essentially free from As or Pd (2: In the Cu-promoted Hiyama process, CuF2 plays the role of two reagents to provide full conversion into the fluoride and copper is also required to transform bulky trialkoxysilanes in situ into CuAr. CuAr immediately transmetalates to Pd, which makes the otherwise inaccessible Pd-catalyzed coupling of bulky arylsilanes feasible and highly efficient.
Stille coupling involving bulky groups feasible with gold cocatalyst
Delpozo, Juan,Carrasco, Desiree,Perez-Temprano, Monica H.,Garcia-Melchor, Max,Alvarez, Rosana,Casares, Juan A.,Espinet, Pablo
, p. 2189 - 2193 (2013/04/10)
Gold shuttle: Bulky groups, which will not (or only very sluggishly) undergo Stille coupling with stannanes and inexpensive ligands, can be efficiently coupled using bimetallic catalysis. A gold cocatalyst serves as an efficient shuttle to convey the bulky group from tin to palladium by reducing the steric crowding in the transition-states (see scheme). Copyright