264133-53-1Relevant academic research and scientific papers
Enantioselective copper catalysed 1,4-conjugate addition reactions using chiral N-heterocyclic carbenes
Winn, Caroline L.,Guillen, Frédéric,Pytkowicz, Julien,Roland, Sylvain,Mangeney, Pierre,Alexakis, Alexandre
, p. 5672 - 5695 (2007/10/03)
The preparation of a variety of chiral N-heterocyclic carbene (NHC) precursors is described. The relative merits of imidazolinium salts and silver carbenes as NHC precursors are discussed with respect to their synthesis, stability and performance in the copper catalysed conjugate addition of dialkyl zinc reagents to a variety of Michael acceptors. Enantioselectivities of up to 93% were achieved using as little as 4% of chiral ligand.
Addition of Grignard reagents to chiral 1,2-bisimines: A diasteroselective preparation of unsymmetrical 1,2-diamines
Roland, Sylvain,Mangeney, Pierre
, p. 611 - 616 (2007/10/03)
A diastereoselective synthesis of tert-butyl-1,2-diamines has been developed from the addition of tert-butylmagnesium chloride to the 1,2- bisimines derived from glyoxal and chiral amines such as 1-(S)- ethylphenylamine, 1-(S)-phenylpropylamine or 1-(S)-(p- chlorophenyl)ethylamine. The influence of solvent, temperature and chiral auxiliaries on the chemical reactivity and stereoselectivity has been fully studied. Evidence of a dynamic kinetic resolution during the bis-addition process of the organometallic, leading to the 1,2-di-tert-butylethanediamine, as a single diastereomer, has been demonstrated. This resolution has been applied with high diastereoselectivities to the synthesis of unsymmetrical disubstituted 1,2-diamines, by addition of one equivalent of tert- butylmagnesium chloride, followed by one equivalent of a second Grignard reagent. Several chiral 1-tert-butyl-1,2-diamines have also been synthesized by monoaddition of tert-butylmagnesium chloride to the bisimines, followed by hydride reduction of the chiral intermediate imines.
