Synthesis of novel H₈-binaphthol-based chiral receptors and their applications in enantioselective recognition of 1,2-amino alcohols and chirality conversion of L-amino acids to D-amino acids

Novel H₈-binaphthol-based chiral receptors appended with an uryl moiety (2a) and a guanidinium moiety (2b) have been designed and synthesized for the enantioselective recognition of 1,2-amino alcohols via reversible imine formation. The selectivities (K_R/K_S = 9.8 ̃ 19.4) of 2b in imine formation with 1,2-amino alcohols are higher than those of 2a (K_R/K_S = 1.8 ̃ 4.5). Similar efficiency trend have been observed in the conversion of L-amino acids to D-amino acids, i.e., the efficiency of the receptor 2b (D/L ratio: 4.3 ̃ 10.1) is superior to 2a (D/L ratio: 4.0 ̃ 8.7).