245110-68-3Relevant articles and documents
Solution structure of a dilithiumamide/diethylzinc heterocomplex that catalyzes asymmetric alkylation reactions
Eriksson, Johan,Arvidsson, Per I.,Davidsson, Oejvind
, p. 2356 - 2361 (1999)
The catalytic complex between diethylzinc and the lithium salt of the chiral piperazine, (2S,5S)-2-isobutyl-5-isopropylpiperazine (1) in THF was investigated by NMR spectroscopy. The lithium salt of 1 was found to undergo fast chair-twisted boat-chair conformational exchange. However, upon addition of one equivalent of diethylzinc this process was found to slow down on the NMR timescale. The piperazine ring in 1 adopts a boat conformation in which the zinc bridges the two amide nitrogens in 1. Small additions of a substrate, for example benzaldehyde, resulted in a dramatic increase of the chair-twisted boat-chair conformational exchange, as seen in the NMR spectra.
Novel chiral N,N′-dimethyl-1,4-piperazines with metal binding abilities
Bérubé, Christopher,Cardinal, Sébastien,Boudreault, Pierre-Luc,Barbeau, Xavier,Delcey, Nicolas,Giguère, Martin,Gleeton, Dave,Voyer, Normand
, p. 8077 - 8084 (2015/12/30)
With the objective of developing novel chiral ligands, we report an efficient strategy to prepare chiral N,N-dimethyl-1,4-piperazines, six-member heterocyclic molecules that possess metal binding features. We prepared and characterized 18 piperazines, and evaluated their ability to complex different mono- and divalent metals, using a rapid picrate extraction technique. Some newly prepared diamine ligands were used in diethylzinc alkylation of aryl aldehydes. Yields increased significantly in the presence of the diamine ligands, though enantioselectivity was low. The results demonstrate the validity of the approach for preparing and identifying useful chiral diamine ligands.
