Iron-Complex-Catalyzed CC Bond Cleavage of Organonitriles: Catalytic Metathesis Reaction between HSi and RCN Bonds to Afford RH and SiCN Bonds

The first example of the catalytic CCN bond cleavage of acetonitrile as well as SiCN bond formation have been achieved in the photoreaction of MeCN with Et3SiH promoted by [Cp(CO)2FeMe]. This catalytic system is applicable to other organonitriles. Several iron complexes [(η5‐C5R5)(CO)2FeR′] (R5=H5, H4Me, Me5, H4SiMe3, H4I, H4P(O)(OMe)2; R′=SiMe3, CH2Ph, Me, Cl, I) were examined as catalyst, and [Cp(CO)2FeMe] was found to be the best precursor. A catalytic reaction cycle was proposed, which involves oxidative addition of Et3SiH to [Cp(CO)FeMe], reductive elimination of CH4 from [Cp(CO)FeMe(H)(SiEt3)], coordination of RCN to [Cp(CO)Fe(SiEt3)], silyl migration from Fe to N in the coordinated RCN, and dissociation of Et3SiNC from Fe. The reaction with MeCN of [Cp(CO)Fe(py)(SiEt3)], which was newly prepared and determined by X‐ray analysis, and the reaction of Et3SiH with MeCN in the presence of a catalytic amount of [Cp(CO)Fe(py)(SiEt3)] showed that the 16‐electron species [Cp(CO)Fe(SiEt3)] is the active species in the catalytic cycle (TON up to 251). Bond exchange: Catalytic CC bond cleavage of acetonitrile and CSi bond formation can be attained by the photoreaction of MeCN with Et3SiH in the presence of [Cp(CO)2FeMe]. This catalytic system is also applicable to other organonitriles.