Organic chemistry: Preparative synthesis of the Corey chiral controller for enantioselective dihydroxylation of olefins

Article abstract of DOI:10.1007/BF02495355

A five-step synthesis of both enantiomers of 1,2-di(2,4,6-trimethylbenzylamino)-1,2-diphenylethane, i.e., Corey (R,R)- and (S,S)-controllers for enantioselective dihydroxylation of olefins by osmium tetroxide, starting from α,α'-diphenylglyoxime, has been developed. The key operations in the synthesis are the optical resolution of intermediate rac-1,2-diamino-1,2-diphenylethane into two enantiomers using only (R,R)-tartaric acid and the subsequent enhancement of the enantiomeric purity to >98% by crystallizations of the corresponding Schiff's bis-bases. Analysis of the enantiomeric purity of the controllers can be easily performed using ¹H NMR spectra of their salts with (R)-α-methoxy-α-(trifluoromethyl)phenylacetic acid (Mosher R-acid).