A thermodynamic preferece of chiral N-methanesulfonyl and N-arenesulfonyl 2,3-cis-3-alkyl-2-vinylaziridines over their 2,3-trans-isomers: useful palladium(0)-catalyzed equilibration reactions for the synthesis of (E)-alkene dipeptide isosteres

摘要

Palladium(0)-catalyzed reactions of N-methanesulfonyl- or N-(arenesulfonyl)-3-alkyl-2-vinylaziri- dines reveal that 2,3-cis-isoers are more stable than the corresponding 2,3-trans-isomers in accord with ab initio calculations. A highly stereoselective synthetic route to (E)-alkene dipeptide isosteres having desired stereochemistries from 2,3-cis-3-isobutyl-2-vinylazitidine by the use of organocopper chemistry is also presented.