Synthesis and Characterization of Some New C 2 Symmetric Chiral Bisamide Ligands Derived from Chiral Feist’s Acid

The hemilabile chiral <em>C<sub>2</sub></em> symmetrical bidentate substituted amide ligands (1<em>R</em>,2<em>R</em>)-<strong>5<sub>a-d</sub></strong> and (1<em>S</em>,2<em>S</em>)-<strong>6<sub>a-d</sub></strong> were synthesized in quantitative yield from (1<em>R</em>,2<em>R</em>)-(+)-3-methylenecyclo-propane-1,2-dicarboxylic acid (1<em>R</em>,2<em>R</em>)-<strong>3</strong> and (1<em>S</em>,2<em>S</em>)-(-)-3-methylene-cyclopropane-1,2-dicarboxylic acid (1<em>S</em>,2<em>S</em>)-<strong>3</strong>, in two steps, respectively. The chiral Feist’s acids (1<em>R</em>,2<em>R</em>)-<strong>3</strong> and<strong> </strong>(1<em>S</em>,2<em>S</em>)-<strong>3</strong> were obtained in good isomeric purity by resolution of <em>trans</em>-(±)-3-methylene-cyclopropane-1,2-dicarboxylic acid from an 8:2 mixture of <em>tert</em>-butanol and water, using (<em>R</em>)-(+)-<em>α</em>-methylbenzyl amine as a chiral reagent. This process is reproducible on a large scale. All these new synthesized chiral ligands were characterized by <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, IR, and mass spectrometry, as well as elemental analysis and their specific rotations were measured. These new classes of <em>C<sub>2</sub></em> symmetric chiral bisamide ligands could be of special interest in asymmetric transformations.

Abstract licence: CC BY

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.