A Masked Cuprous Hydride as a Catalyst for Carbonyl Hydrosilylation in Aqueous Solutions

Monomeric Cu(HBPh₃) supported by an N‐heterocyclic carbene is thermally stable and catalyzes the carbonyl hydrosilylation in water as a co‐solvent.

Abstract

Redox‐unstable cuprous hydridotriphenylborate was isolated as an N‐heterocyclic carbene adduct [(IPr)Cu(HBPh₃)] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) with good thermal stability. Although this compound displays a contact ion‐pair structure, Cu^IH‐like catalytic activity was envisaged in carbonyl hydrosilylation. Sufficient moisture stability allowed the catalysis in aqueous/organic media. Mechanistic study further showed that a phenyl group on the borate anion is abstracted by [(IPr)Cu]⁺ to give the cationic organocopper complex [(IPr)₂Cu₂(μ‐Ph)][BPh₄].

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