Abstract
Synthesis, properties and applications to transition metal catalysis of extremely compact, caged trialkylphosphines (SMAPs) in the form of molecules or silica–supported materials are described. The new phosphines are air–stable despite their strongly electron–rich character. Soluble phosphine Ph–SMAP showed high ligand performance in the Rh–catalyzed hydrosilylation and hydrogenation of ketones. The silica–supported SMAP (Silica–SMAP) displayed a unique coordination behavior to form 1:1 P–metal complexes, which appeared to be useful as platforms to create highly active catalytic centers. As a result, Silica–SMAP enabled the Rh–catalyzed hydrosilylation and hydrogenation of extremely hindered ketones such as di–tert–butyl ketone as well as Ir–catalyzed directed ortho–borylation of functionalized arenes with a broad substrate scope.
