Activation of TMSCN by N-heterocyclic carbenes for facile cyanosilylation of carbonyl compounds.

N-Heterocyclic carbenes were found to be highly effective organocatalysts in activating TMSCN for facile cyanosilylation of carbonyl compounds. Cyano transfer from TMSCN to aldehydes and ketones proceeds at room temperature in the presence of only 0.01-0.5 mol % of N-heterocyclic carbene (1), leading to a range of trimethylsilylated cyanohydrins in very good to excellent yields. These conditions are extremely mild and simple and tolerate various functional groups.