Selective Host Amplification from a Dynamic Combinatorial Library of Oligoimines for the Syntheses of Different Optically Active Polyazamacrocycles

Abstract

Two different macrocyclic hosts are amplified and expressed by metal guests from the same dynamic combinatorial library (DCL) of oligoimines. We studied the thermodynamic template effect and the structure of the final compounds by a combination of ESI-MS, UV and NMR spectroscopy, and Xray crystallography techniques. The use of Ba II or Cd II metal salts allows the selective synthesis of dimeric [2+2] or trimeric [3+3] cyclic structures, respectively. We observed a cooperative molding effect for the Cd ion-templated process. A study of the DCL behavior in situ demonstrated a second level of molecular diversity, based on the imine/α-methoxy-

Designed Folding of Pseudopeptides: The Transformation of a Configurationally Driven Preorganization into a Stereoselective Multicomponent Macrocyclization Reaction

“…Its chairlike conformation, with the CÀN bonds forming angles of 608, has served as an excellent scaffold for the construction of large conformationally restricted macrocycles and pincers. Thus, this diamine can undergo either [2 + 2] or [3 + 3] cyclocondensation reactions, [26] generate a dynamic covalent system, [27] or induce important constraints when forming part of a longer open-chain molecule. [28] In our pseudopeptidic molecules, the cyclohexane frame induces a turn conformation in the linear precursors, which favors the [2 + 2] cyclization process.…”

Conformational Control in Metallofoldamers: Design, Synthesis and Structural Properties

“…The chiral macrocycle L was obtained in the enantiopure forms L RRRRRR and L SSSSSS , corresponding to all-R or all-S configuration of the diaminocyclohexane carbon atoms, respectively. [26] Mixing of ligand L with Ln 3+ precursors (Ln = Eu, Tb, Yb) resulted in the formation of metal complexes, as indicated by 1 H NMR spectroscopy, which were further isolated as enantiopurenitrate salts. The X-ray crystal structure of (M)-…”

Protonated Hexaazamacrocycles as Selective K+ Receptors

“…The racemate of the hexaazamacrocycle M was synthesized and purified according to our modifications of the procedures reported in the literature [17,24,26] (see Supplementary Scheme S1). Each step of the reaction sequence was monitored by thin-layer chromatography and HPLC-ESI-mass spectrometry.…”