The asymmetric dialkylzinc addition to imines catalyzed by [2.2]paracyclophane-based N,O-ligands.
The first highly enantioselective dialkylzinc addition to imines in the presence of catalytic amounts of N,O-ligands is reported. N-formyl-alpha-(p-tolysulfonyl)benzylamines are the readily available starting materials easily obtained in a one-pot synthesis from benzaldehydes, formamide, and p-tolylsulfinic acid. Upon deprotonation, the sulfinate is eliminated to give the acyl imine. The acyl imines further react with alkylzinc reagents in the presence of catalytic amounts of [2.2]paracyclophane-based N,O-ligands L yielding the alkylated N-(1-phenylpropyl)formamides with excellent yields and enantioselectivities.
Dahmen
Stefan
S
Kekulé-Institut für Organische Chemie und Biochemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany.
Bräse
Stefan
S