| Abstract
| - A new synthesis of 2,3-disubstituted pyrrolidines and piperidines is described. This mild procedureis based on the one-pot oxidative decarboxylation−β-iodination of α-amino acid carbamates oramides. The iodine is introduced at the previously unfunctionalized 3-position. Different substituentscan be introduced at C-2, e.g., hydroxy, alkoxy, allyl, alkyl, etc. A trans relationship between theC-2 and C-3 substituents is exclusively obtained. The influence of the solvent and the ring size ofthe starting amino acid are studied, as well as the nature of the protecting group on the nitrogen.The stereoselectivity of the reaction was also studied using chiral methyl (2S,4S)-4-acetyloxyproline-1-carboxylate (8). The products obtained can be manipulated to give bicyclic systems present inmany natural products. By using the tandem decarboxylation−iodination−alkylation reaction,2-substituted-3-iodopyrrolidines are formed, which are precursors of 2-substituted-2,5-dihydropyrrols.
|
