Breaking C–O Bonds with Uranium: Uranyl Complexes as Selective Catalysts in the Hydrosilylation of Aldehydes

• Published in: ACS catalysis Vol. 9; no. 10; pp. 9025 - 9033
• Main Authors: Monsigny, Louis, Thuéry, Pierre, Berthet, Jean-Claude, Cantat, Thibault
• Format: Journal Article
• Language: English
• Published: American Chemical Society 04-10-2019
• Subjects: Chemical Sciences; Coordination chemistry; Organic chemistry; aldehydes; homogeneous catalysis; uranyl; hydrosilylation; uranium; reduction; mechanisms; Reduction; Mechanisms; Uranium; Homogenous catalysis; Hydrosilylation; Aldehydes; Uranyl
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.9b01408

We report herein the possibility to perform the hydrosilylation of carbonyls using actinide complexes as catalysts. While complexes of the uranyl ion [UO2]2+ have been poorly considered in catalysis, we show the potentialities of the Lewis acid [UO2(OTf)2] (1) in the catalytic hydrosilylation of a series of aldehydes. [UO2(OTf)2] proved to be a very active catalyst affording distinct reduction products depending on the nature of the reductant. With Et3SiH, a number of aliphatic and aromatic aldehydes are reduced into symmetric ethers, while i Pr3SiH yielded silylated alcohols. Studies of the reaction mechanism led to the isolation of aldehyde/uranyl complexes, [UO2(OTf)2(4-Me2N-PhCHO)3], [UO2(μ-κ2-OTf)2(PhCHO)] n , and [UO2(μ-κ2-OTf)­(κ1-OTf)­(PhCHO)2]2, which have been fully characterized by NMR, IR, and single-crystal X-ray diffraction.