Computer-assisted discovery of novel amino acid derived sulfides for enantioselective epoxidation of aldehydes

With the aid of molecular modeling, thiazolidine derivatives have been designed as catalysts for epoxidation of aldehydes. Accessible from amino acids, the thiazolidine derivatives can be synthesized in both enantiomeric forms and with a diverse array of substituents. A representative member, (S)-N-tert-butoxycarbonyl-2,2-dimethyl-4-isopropyl thiazolidine, of the thiazolidine family has been prepared, and it has been shown to catalyze the formation of trans-stilbene oxide with high enantioselectivity. Experimental and theoretical characterization has allowed the evaluation of the factors affecting enantioselectivity, facilitating the design of second-generation thiazolidines and other chiral sulfides as epoxidation catalysts.