Stereoselective synthesis of topologically chiral molecular entanglements

Molecules such as knots and catenanes can exhibit topological chirality resulting from their entangled nature. Controlling the handedness of this chirality, especially beyond the simplest systems, is a significant synthetic challenge. In this issue of Chem, Zhang and co-workers have realized the stereoselective synthesis of both a cinquefoil (51) knot and a triply braided, Star of David [2]catenane ( 6 1 2 link). Gaining such control over these higher-order molecular entanglements expands their potential use in sensing, catalysis, and materials applications. Molecules such as knots and catenanes can exhibit topological chirality resulting from their entangled nature. Controlling the handedness of this chirality, especially beyond the simplest systems, is a significant synthetic challenge. In this issue of Chem, Zhang and co-workers have realized the stereoselective synthesis of both a cinquefoil (51) knot and a triply braided, Star of David [2]catenane ( 6 1 2 link). Gaining such control over these higher-order molecular entanglements expands their potential use in sensing, catalysis, and materials applications. A Star of David [2]catenane of single handednessFeng et al.ChemDecember 5, 2022In BriefEfficient synthesis of topologically chiral links with controlled handedness is challenging, despite several molecular prime links that have been prepared. Here, we described the two-step highly stereoselective synthesis of a Star of David [2]catenane ( 6 1 2 ). Use of CHIRAGENs containing chiral centers closed to coordination sites allows the transfer of the point chirality of the ligands to the topological chirality of the resulting link. This study opens the way to explore the development and potential of topological stereochemistry in chemistry and beyond. Full-Text PDF Completely stereospecific synthesis of a molecular cinquefoil (51) knotZhang et al.ChemDecember 5, 2022In BriefWe have reported the highly stereoselective synthesis of a molecular 51 knot containing chiral valine units affording both enantiomers. The chirality of the valine group determines the handedness of the molecular knots. Transfer of chirality in knot synthesis opens up opportunities for the assembly of other topologically chiral nanotopologies and probing the implications of topological stereochemistry in chemistry, materials, and biology. Full-Text PDF