Homochiral 2,2'-bis(oxazolyl)-1,1'-binaphthyls as ligands for copper(I)- catalyzed asymmetric cyclopropanation

Article abstract of DOI:10.1016/0957-4166(96)00193-0

Homochiral 2,2'-bis[4-(alkyl)oxazol-2-yl]-1,1'-binaphthyls, which possess both binaphthyl axial chirality and carbon centred chirality, were prepared from 1,1'-binaphthyl-2,2'-dicarboxylic acid and 2-alkyl-2-aminoethanols in high yields. Asymmetric cyclopropanation of styrene with diazoacetates in the presence of 2 mol % of copper(I) triflate and (S)-2,2'-bis[(S)-4-(t- butyl)oxazol-2-yl]-1,1'-binaphthyl gave optically active 2- (phenyl)cyclopropane-carboxylates of up to 97% ee.