Cyanosilylation of Aldehydes Catalyzed by Iron(III) Arylhydrazone-beta-Diketone Complexes

Two known iron(III) complexes, [Fe(H2O)(3)(L-1)]center dot xH(2)O (x = 4 (1), 5 (2)) and [Fe(H2O)(3)(L-2)]center dot 3H(2)O (3), bearing the basic forms of 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonic acid (H3L1) and 3-(2-(2,4-dioxopentan-3-ylidene) hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonic acid (H3L2), were prepared and used as homogeneous catalysts for cyanosilylation of a variety of aldehydes with trimethylsilyl cyanide leading to the corresponding cyanohydrin trimethylsilyl ethers. High yield (up to 98 %) was observed in the reaction catalyzed by 3 at room temperature in methanol.