77897-23-5Relevant articles and documents
Catalytic Asymmetric Synthesis of Morpholines. Using Mechanistic Insights to Realize the Enantioselective Synthesis of Piperazines
Lau, Ying Yin,Zhai, Huimin,Schafer, Laurel L.
, p. 8696 - 8709 (2016/10/14)
An efficient and practical catalytic approach for the enantioselective synthesis of 3-substituted morpholines through a tandem sequential one-pot reaction employing both hydroamination and asymmetric transfer hydrogenation reactions is described. Starting from ether-containing aminoalkyne substrates, a commercially available bis(amidate)bis(amido)Ti catalyst is utilized to yield a cyclic imine that is subsequently reduced using the Noyori-Ikariya catalyst, RuCl [(S,S)-Ts-DPEN] (η6-p-cymene), to afford chiral 3-substituted morpholines in good yield and enantiomeric excesses of >95%. A wide range of functional groups is tolerated. Substrate scope investigations suggest that hydrogen-bonding interactions between the oxygen in the backbone of the ether-containing substrate and the [(S,S)-Ts-DPEN] ligand of the Ru catalyst are crucial for obtaining high ee's. This insight led to a mechanistic proposal that predicts the observed absolute stereochemistry. Most importantly, this mechanistic insight allowed for the extension of this strategy to include N as an alternative hydrogen bond acceptor that could be incorporated into the substrate. Thus, the catalytic, enantioselective synthesis of 3-substituted piperazines is also demonstrated.
Combined Imine Reductase and Amine Oxidase Catalyzed Deracemization of Nitrogen Heterocycles
Heath, Rachel S.,Pontini, Marta,Hussain, Shahed,Turner, Nicholas J.
, p. 117 - 120 (2016/01/26)
A novel amine oxidase (AO)/imine reductase (IRED) system was developed for the deracemization of racemic amines. By combining (R)-6-hydroxy-d-nicotine oxidase (6-HDNO) with an (R)-IRED, a panel of racemic 2-substituted piperidines and pyrrolidines were deracemized to yield the (S)-amines in high yields and enantiomeric excess values. Other N-heterocycles were deracemized with monoamine oxidase (MAO-N) or 6-HDNO in combination with ammonia borane, which allowed comparison of the two enzyme deracemization approaches with that involving a chemical reducing agent.
KINETIC RESOLUTION OF CHIRAL AMINES
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Page/Page column 111; 112; 113, (2013/03/26)
The present invention refers to a method for the kinetic resolution of a chiral primary or secondary amine by treating the amine with a chiral, hydroxamic acid derived reagent of the formula (I). These chiral reagents are particularly useful for the kinetic resolution of cyclic amines and may be generated in situ in the presence of an N-heterocyclic carbene, thus allowing for a catalytic reaction.