Chiral N-heterocyclic biscarbenes based on 1,2,4-triazole as ligands for metal-catalyzed asymmetric synthesis.
A facile and straightforward synthetic procedure for the preparation of new chiral bis-1,2,4-triazolium salts and their corresponding rhodium(I) biscarbene complexes are reported. It is widely applicable for the synthesis of 1,2,4-triazolium salts. The new chiral biscarbenes represent promising ligands for transition metal-catalyzed asymmetric syntheses. Their first successful application is demonstrated by the rhodium-catalyzed hydrogenation of dimethylitaconate and methyl-2-acetamidoacrylate which yielded enantioselectivities of up to 61% ee.
Institut für Siliciumchemie, Lehrstuhl für Anorganische Chemie, Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85747, Garching b. München, Germany.
Stephanie K U
SK
Riederer
Bettina
B
Bechlars
Wolfgang A
WA
Herrmann
Fritz E
FE
Kühn