Rhodium-Catalyzed Hydrosilylation Of Ketones Research Articles

Transition-Metal Catalysis with Hollow-Shaped Triethynylphosphine Ligands

Abstract Triethynylphosphines with bulky end caps such as triarylsilyl and triarylmethyl groups at alkyne termini have a novel molecular shape presenting a large, deep metal-binding cavity. The hollow-shaped triethynylphosphines functioned as effective ligands in the rhodium-catalyzed hydrosilylation of ketones with triorganosilanes due to the preferential formation of a mono-P-ligated rhodium species. Furthermore, the phosphines displayed remarkable rate enhancement in the gold(I)-catalyzed alkyne cyclization constructing six- to eight-membered ring compounds. It is proposed that the cavity in the ligand forces a nucleophilic center of the acetylenic compounds close to the gold-bound alkyne, making ring-closing anti attack feasible.