[chemical reaction: see text]. A toluene-coordinated silyl borate, [Et3Si(toluene)]B(C6F5)4, demonstrated catalytic activities significantly higher than those of Me3SiOTf and Me3SiNTf2 in Mukaiyama aldol and Diels-Alder reactions.

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Solid-supported phosphine ligands silica−SMAPs {[silica gel 60N]−SMAP (1a) or [CARiACT Q-10]−SMAP (1b)}, which are composed of a caged, compact trialkylphosphine (SMAP) as a ligand and silica gel (silica gel 60N or CARiACT Q-10) as a support, were synthesized through surface functionalization. The supported phosphines (1a,b) were structurally characterized by solid-state 13C, 29Si, and 31P cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopies and N2 adsorption measurements. Complexation of 1a,b with [RhCl(cod)]2 afforded a mono(phosphine)-rhodium complex Silica−SMAP−RhCl(cod) exclusively, even in the presence of excess ligands, as proved by solid-state 13C and 31P CP/MAS NMR spectroscopies and Rh K-edged X-ray absorption fine structure (XAFS) measurements. Heterogeneous catalysts that were prepared from [RhCl(C2H4)2]2 and 1a,b showed exceptionally high catalytic activities for the reaction of sterically hindered ketones (including di-tert-butyl ketone) and triorganosilanes such as Et3SiH and (t-Bu)Me2SiH. The catalyst from 1b showed no leaching of rhodium after reaction and was reusable without decrease of the activity.