Hydrazines and hydroxylamines have been found to be excellent nucleophiles for the palladium-catalyzed dynamic asymmetric allylic amination of vinyl epoxide, with good yields and enantioselectivities of up to 97% ee. This method is applicable to acyclic and heterocyclic amines and was applied toward a five-step synthesis of (R)-piperazic acid.
Highly efficient synthesis of (R)- and (S)-piperazic acids using proline-catalyzed asymmetric α-hydrazination
The highly efficient synthesis of (R)- and (S)-piperazic acids, components of naturally occurring antibiotic cyclodepsipeptides, was achieved in 80% overall yield by the use of a proline-catalyzed asymmetric alpha-hydrazination as the key step. (C) 2004 Elsevier Ltd. All rights reserved.