Cu(i)-SNS complexes for outer-sphere hydroboration and hydrosilylation of carbonyls.

Two new NHC-Cu(i)-[κ2-SNS] complexes were synthesized to directly compare the bifunctional catalytic activity of a hard amido vs. a soft thiolate donor. The Cu thiolate complex catalyzed ketone hydroboration but not hydrosilylation, while the Cu amido complex is a high-performing outer-sphere carbonyl reduction catalyst using boranes and silanes.