Nanoceria as a recyclable catalyst/support for the cyanosilylation of ketones and alcohol oxidation in cascade

[EN] The cyanosilylation of carbonyl compounds is a fundamental reaction in organic synthesis, to give cyanohydrins. Ketones are particularly reluctant to cyanosilane addition and require the action of a catalyst, and despite many soluble Bronsted and Lewis acids have been employed for this task, it is difficult to find in the open literature catalytic solids able to carry out the reaction. Here, we show that commercially available nanoceria catalyzes the cyanosilylation of different ketones (21 examples) at temperatures between 0 and 50 degrees C, in high yields, under solventless conditions if required. The nanoceria network atoms act in a cooperative way to provide a bifunctional acid-base solid catalyst for the cyanosilylation reaction. The amorphization of nanoceria during reaction, due to acid release, does not hamper the catalytic activity and, indeed, different types of nanoceria, even with supported metal nanoparticles on surface, are active for the reaction, enabling extensive reuses after air calcination and the use of the catalytic material for the aerobic oxidation of alcohols / cyanosilylation reaction. (C) 2020 Elsevier Inc. All rights reserved.
Financial support by MINECO (Spain) (Project CTQ 2017-86735P and Excellence Unit "Severo Ochoa"SEV-2016-0683) is acknowledged. F.G.-P. thanks ITQ for a contract and M.A.R-C. thanks Iberdrola Foundation for a fellowship.