Vanadium-Catalyzed Enantioselective Cyanoformylation of Aldehydes

Significance

Enantioselective addition of cyanide to aldehyde has been of interest for many years and many catalytic systems have been described using V⁵⁺ complexes. In this report, a cyanoformylation of aldehydes using a chiral vanadium salen catalyst, an imidazole cocatalyst, and ethyl cyanoformate is described. The yields and enantioselectivities are good for aromatic and aliphatic aldehydes. For crystalline products, the enantioselectivities can be further improved by recrystallization. Advantageously, the cyanohydrin products are more stable towards hydrolysis than cyanohydrin trimethylsilyl ethers.