Magrez-Chiquet M, Morin MS. T, Wencel-Delord J, Amraoui SD, Baslé O, Alexakis A, Crévisy C, * Mauduit M. * Ecole Nationale Supérieure de Chimie de Rennes, France and Université de Genève, Switzerland
Enantioselective 1,6-Conjugate Addition of Dialkylzinc Reagents to Acyclic Dienones Catalyzed by Cu-DiPPAM Complex–Extension to Asymmetric Sequential 1,6/1,4-Conjugate Addition.
Chem. Eur. J. 2013;
19: 13663-13667
Key words
copper - dialkylzinc - conjugate addition
Significance
The authors reported the asymmetric 1,6-conjugate addition of dialkylzinc to acyclic dienones catalyzed by copper/phosphinoazomethinylate salt (DiPPAM). After the isomerization of the conjugate adducts, stereoselective sequential 1,4-conjugate addition of diethylzinc was also demonstrated.
Comment
The control of regioselectivity of the 1,6-conjugate addition is difficult due to many parameters. Using copper and the DiPPAM ligand, a highly enantio- and regioselective 1,6-conjugate addition was achieved. With the BINAP ligand, unprecedented highly stereoselective induction is noteworthy.
