845965-28-8Relevant articles and documents
Enantioselective Silver and Amine Co-catalyzed Desymmetrizing Cycloisomerization of Alkyne-Linked Cyclohexanones
Manzano, Rubén,Datta, Swarup,Paton, Robert S.,Dixon, Darren J.
, p. 5834 - 5838 (2017/05/12)
A silver(I) and amine co-catalyzed desymmetrization of 4-propargylamino cyclohexanones for the direct enantioselective synthesis of 2-azabicyclo[3.3.1]nonanes is described. Exploiting reactivity arising from dual activation of the pendant terminal alkyne by silver(I) and the ketone moiety through transient enamine formation, this synthetically relevant transformation is easy to perform, efficient and broad in scope. High enantioselectivity (up to 96 % ee) was achieved by exploiting a significant matching effect between the chirality of a cinchona alkaloid-derived aminophosphine ligand for the silver(I) salt and the 2-bis(aryl)methylpyrrolidine catalyst which was rationalized by DFT calculations. This allowed for the preparation of both enantiomers of the bicyclic product with near-identical stereocontrol.
Fluorinated chiral secondary amines as catalysts for epoxidation of olefins with oxone
Ho, Chun-Yu,Chen, Ying-Chun,Wong, Man-Kin,Yang, Dan
, p. 898 - 906 (2007/10/03)
(Chemical Equation Presented) We have synthesized a series of chiral cyclic secondary amines having different substitution patterns and have screened them as catalysts for the asymmetric epoxidation of olefins using Oxone. The highest enantiomeric excess (61%) occurred for the epoxidation of 1-phenylcyclohexene catalyzed by a secondary amine bearing a fluorine atom at the β-position relative to the amino center. Our experimental results provide further support to the notion that the amine plays a dual role - as a phase transfer catalyst and an Oxone activator - in these epoxidation reactions. The slightly acidic reaction conditions we employed in this work obviate the need to preform ammonium salts, which are the actual catalysts that mediate the epoxidations.
