Easily recyclable polymeric V(V) salen complex for the enantioselective O-acetyl cyanation of aldehydes

A new recyclable polymeric V(V) salen complex 1 derived from poly[(R,R)-N,N′-bis-{3-(1,1-dimethylethyl)-5-methylene salicylidene} cyclohexane 1,2-diamine] with vanadyl sulphate was synthesized and characterized by microanalysis, 1H NMR, optical rotation, IR, and UV–vis spectroscopy. The complex 1 was used as catalyst for asymmetric O-acetyl cyanation of various aldehydes with KCN as an inexpensive and non-volatile cyanide source and acetic anhydride at −20 °C. High chiral induction (ee, 96%) for O-acetylcyanohydrin was obtained in the case of 2-methylbenzaldehyde with added advantage of catalyst recyclability.

Figure optionsDownload as PowerPoint slide