Development of biisoquinoline-based chiral diaminocarbene ligands: enantioselective SN2' allylic alkylation catalyzed by copper-carbene complexes.
Chiral biisoquinoline-based diaminocarbene ligands (BIQ) were designed to create a chiral environment extended toward the metal center, which was confirmed by an X-ray structure. The concise ligand synthesis is highlighted by a modified Bischler-Napieralski cyclization of bisamides prepared from readily available chiral phenethylamines, and allows easy variation of the stereodifferentiating groups. The cyclohexyl-BIQ-copper complex is an efficient catalyst for enantioselective SN2' allylic alkylation with Grignard reagents showing SN2' regioselectivity higher than 5:1 and enantioselectivity in the range of 68-77% ee.
Seo
Hwimin
H
Department of Chemistry, University of Florida, PO Box 117200, Gainesville, Florida 32611-7200, USA.
Hirsch-Weil
Dimitri
D
Abboud
Khalil A
KA
Hong
Sukwon
S