565230-22-0Relevant academic research and scientific papers
Regioselective formation of endo- and exo- cyclic enamines: Both enantiomeric products accessible by the same chiral auxiliary
Christoffers, Jens,Kreidler, Burkard,Oertling, Heiko,Unger, Sven,Frey, Wolfgang
, p. 493 - 496 (2003)
The copper-catalyzed conversion of exo-cyclic enamines 4a-c with methyl vinyl ketone (2) yields spirocyclic products 6a-c in a sequence of Michael and aldol reaction. The application of the chiral auxiliary L-valine diethylamide results in the formation o
Generation of quaternary stereocenters by asymmetric Michael reactions: Enamine regiochemistry as configuration switch
Kreidler, Burkard,Baro, Angelika,Frey, Wolfgang,Christoffers, Jens
, p. 2660 - 2667 (2007/10/03)
Regioselective enamine formation from cyclic β-diketones 1 is obtained by the appropriate choice of activating agent: Bronsted acid catalyzed condensation gives endocyclic enamines 3 as the thermodynamically favored products. Activation with Lewis acid BF
Regioselective enamine formation from oxonia-boranuida-betaines and their application in asymmetric Michael reactions
Christoffers, Jens,Kreidler, Burkard,Unger, Sven,Frey, Wolfgang
, p. 2845 - 2853 (2007/10/03)
β-Diketonato borate betaines 2 are readily accessible by the reaction of β-dicarbonyl compounds 1 with BF3·OEt2. Reaction of borates 2 with L-valine diethylamide (3a) gives almost exclusively the exocyclic enamines 4 as the kinetic p
