Structurally diverse second-generation [2.2]paracyclophane ketimines with planar and central chirality: syntheses, structural determination, and evaluation for asymmetric catalysis.
A set of 20 novel [2.2]paracyclophane ketimines with planar and central chirality has been synthesized from enantiomerically pure and racemic 5-acyl-4-hydroxy[2.2]paracyclophane and alpha-branched chiral amines. Their X-ray structures were determined to elucidate the three-dimensional structures and the absolute configuration. The ketimines were used as catalysts in the asymmetric 1,2-addition reactions of diethylzinc with substituted benzaldehydes to furnish chiral alcohols in up to 95 % ee.
Lauterwasser
Frank
F
Institut für Organische Chemie, Universität Karlsruhe TH, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
Nieger
Martin
M
Mansikkamäki
Heidi
H
Nättinen
Kalle
K
Bräse
Stefan
S