SYNTHESIS OF C-ALKYLCALIX[4]ARENES .4. DESIGN, SYNTHESIS, AND COMPUTATIONAL STUDIES OF NOVEL CHIRAL AMIDO[4]RESORCINARENES

In extending our studies involving BF3-Et(2)O-catalyzed reaction of ci nnamic acid analogues, we have shown that amido derivatives also can a fford [4]resorcinarene octamethyl ethers. Subsequently, chiral monomer ic amides, derived from the mixed anhydride of cinnamic acid and L- or D-valine, upon treatment with BF3-Et(2)O, yielded for the first time chiral amido [4]resorcinarenes in enantiomerically pure forms. Four st ereoisomers were isolated, and three of them were attributed the flatt ened-cone, chair, and 1,2-alternate conformations. The major product w as assigned a novel chairlike structure, namely flattened partial cone 1. The flattened-cone stereoisomer which was indicated by molecular m odeling studies to be the most stable, became the major product under more drastic experimental conditions. Chromatographic studies an chira l phases revealed that the above tetramers could be used for the enant iodiscrimination of racemic molecules.