Synthesis of new N,N′-bichiral lariat crown ethers and their application

Two N,N'-bichiral lariat crown ethers, (S,S)-1,7-bis(4-benzyl-5-hydroxy-2-oxo-3-azapentyl)-1,7-diaza-12-crown-4 (1a) and (S,S)-1,7-bis(4-benzyloxazolin-2-yl-methyl)-1,7-diaza-12-crown-4 (1b), were obtained by alkylation of 1,7-diaza-12-crown-4 with (S)-(1-hydroxy-3-phenylprop-2-yl)-chloroacetamide or (S)-2-chloromethyl-4-benzyloxazoline, which were obtained by the reaction of (S)-2-amino-3-phenylpropanol with triethyl orthochloroacetate. la was used successfully in the chiral separations of D/L-carnitine by capillary zone electrophoresis. Cu(II) complex of 1b was applied to the asymmetric cyclopropanation of 1,1-diphenylethylene with alkyl diazoacetate.