Facile Separation of Catalyst and Byproducts by Self-Encapsulation

Significance

An efficient reduction of carboxamides to amines with polymethylhydrosiloxane ­(PMHS) was accomplished using a ruthenium cluster, (µ₃,η²:η³:η⁵-acenaphthylene)Ru₃(CO)₇ (1) as the catalyst. After completion of the reaction, the catalyst species was encapsulated into the insoluble cross-linked siloxane formed during the reaction, leading to the facile separation of both metallic and siloxane residues from the desired products. Namely, this catalysis consists of two simultaneous processes: reduction of carboxamides and removal of the catalyst and polymeric by-products from the resulting amines. Furthermore, the recovered silicone resin in which the Ru complex was encapsulated could be reused as the catalyst for the reduction in the presence of additional PMHS.