Enantioselective synthesis of [1,2]-oxazinone scaffolds and [1,2]-oxazine core structures of FR900482
摘要:
Several chiral unsaturated [1,2]-oxazinone heterocycles have been synthesized by iridium-catalyzed allylic substitution and ring-closing metathesis (RCM) reaction in high yields with excellent enantiomeric excesses. In addition, the synthesis of [1,2]-oxazine core structures of FR900482 was achieved via iridiurn-catalyzed allylic substitution, followed by RCM and Heck reactions, respectively. (c) 2007 Elsevier Ltd. All rights reserved.
Utility of the Iridium Complex of the Pybox Ligand in Regio- and Enantioselective Allylic Substitution
摘要:
[GRAPHICS]The viability of the iridium complex of pybox as chiral catalyst in allylic substitutions and the enantiosilective synthesis of branched products was studied. Among several chiral ligands evaluated, the iridium complex of pybox having a phenyl group catalyzed the reaction with high activity to form the branched amines with good enantioselectivities when hydroxylamine, amine, and aniline were employed as a nucleophile. The allylic substitution with oximes proceeded smoothly to give the branched oxime ethers with good enantioselectivities.