Synthesis of azophenolic crown ethers of C s symmetry incorporating cis-1-phenylcyclohexane-1,2-diol residues as a steric barrier and diastereotopic face selectivity in complexation of amines by their diastereotopic faces
Azophenolic crown ethers 1 and 2 of C-s symmetry incorporating cis-1-phenylcyclohexane-1,2-diol residues as a steric barrier have been prepared. Diastereotopic face selectivity in complexation with 2-methoxyethylamine, n-propylamine and ethanolamine was examined using temperature-dependent H-1 NMR spectroscopy. Both bind ethanolamine stereoselectively to one of their diaseereotopic faces; the prediction of which diastereoisomeric complexwas preferentially formed is made on the basis of a CPK molecular-model examination ofthe complexes.
Naemura, Koichiro; Miyabe, Hajime; Shingai, Yasuhiro, Journal of the Chemical Society. Perkin transactions I, 1991, # 4, p. 957 - 959