Synthesis and structure of chiral 2,6-bis[(2-carbamoylphenyl)carbamoyl]pyridine ligands
摘要:
The synthesis and structure of a series of enantiomerically pure 2,6-bis[(2-carbamoylphenyl)carbamoyl]-pyridine ligands (H(2)a-c) are described. Appended from the aryl groups are optically active groups which provide a chiral environment around the planar pyridine core. NMR and X-ray diffraction studies show that these ligands contain helical character which is maintained by a network of intramolecular hydrogen bonds. These ligands can bind metal ions through their tridentate diamidato-pyridyl chelate to form optically active metal complexes. The modular design of these ligands offers a variety of chiral environments about the metal chelate that can be useful in the synthesis of metal reagents for asymmetric transformations. (C) 1998 Elsevier Science Ltd. All rights reserved.
An Improved Aldehyde Linker for the Solid Phase Synthesis of Hindered Amides
作者:Mark J. Liley、Tony Johnson、Susan E. Gibson
DOI:10.1021/jo051742j
日期:2006.2.1
A novel aldehyde dual-linker system has been developed for the solidphasesynthesis of sterically hindered amides. The linker [5-(4-formyl-3-hydroxyphenoxy)pentanoic acid] exploits an intramolecular oxygen−nitrogen acyl transfer mechanism to prepare compounds that are unattainable with current commercially available linkers. A dual linker system, exploiting the hyper-acid labile Sieber amide linker