Enantioselective cyanoformylation of aldehydes using a recyclable dimeric cinchonidine ammonium salt as an organocatalyst

A dimeric anthracenyldimethyl-derived cinchonidine ammonium salt is used as a chiral organocatalyst in the enantioselective addition of alkyl cyanoformates to aldehydes in the presence of substoichiometric amounts of triethylamine. Quantitative yields and enantioselectivities up to 88% ee for the corresponding (R)-O-methoxycarbonyl cyanohydrins are obtained using only 1 mol % organocatalyst loading and working at 10 °C. The organocatalyst can be almost quantitatively recovered by precipitation and reused.

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