Chirality control of a Cu(I)·(phenanthroline)2 complex by a sugar–boronic acid interaction. A preliminary step toward the total chain helicity control by a chain-end sugar-binding

Abstract

Compounds 1a and 1b which have a 1,10-phenanthroline moiety, were synthesized in order to form a helical structure in the presence of Cu(I), and a boronic acid moiety with which to bind a saccharide at the chain end. When saccharides were added, the Cu(I) complexes (as 1a₂·Cu(I) and 1b₂·Cu(I)) gave the CD-active species reflecting the absolute configurational structure of saccharides. Thus, the P versus M helicity of the complexes can be controlled by the boronic acid–saccharide interaction. The results show that the terminal boronic acid group is useful to create the chiral helical structure and the total helicity is governed by the chirality of the boronic acid-bound saccharide.