Silylation, decyanative

Scheme 14 A plausible mechanism for rhodium-catalyzed decyanative silylation of nitriles [RhCI(cod)]2 (5 mol %)...

Scheme 15 Decyanative silylation of nitriles catalyzed by rhodium...

It has been reported that aryl-to-aryl 1,5-rhodium migration is involved in decyanative silylation of aryl cyanides bearing a tethered arene. The 1,5-migration proceeds through remote C-H bond activation (Scheme 148). " ... 

Hydroxyl function protecting group (in particular for ribonucleotides). Reagent for oxid. decyanations. Silylation reagent for use in chromatog. Mp 91.5°. BP733 125°. 

Alternatively, iron- or rhodium-catalyzed hydrodecyanation reaction is proposed to be initiated by the C-CN activation of aromatic and aliphatic nitriles with silylmetal species to give iminoacylmetal intermediates and then sUylisonitrile metal complexes, which produce decyanated products and silyl cyanides upon the reaction with hydrosUanes to reproduce the catalyticaUy active silylmetal intermediates (Scheme 7). Irradiation is required to generate coordinatively unsaturated iron complexes (Scheme 8) [45, 46]. A similar reaction mechanism also operates... 

C-CN bond activation by silylrhodium species can be applied to a catalytic cycle for silylative decyanation of nitriles, when rhodium intermediates active in C-CN activation are generated from disilanes instead of hydrosilanes (Scheme 14). The reaction proceeds with a range of nitriles, including aryl, alkenyl, and alkyl cyanides, to give the corresponding tetraorganosilanes (Scheme 15) [53, 57], although the yields of tetra-alkylsilanes are modest. 

---