Microwave-assisted transition-metal-catalyzed synthesis of N-shifted and ring-expanded buflavine analogues.
Two novel and efficient strategies for the synthesis of hitherto unknown N-shifted and ring-expanded buflavine analogues are presented. Construction of the medium-sized ring system of the title molecules, a difficult task due to the high activation energy needed for the ring-closure with the additional rigidity imposed by the biaryl skeleton, was achieved by using Suzuki-Miyaura biaryl coupling and a ring-closing metathesis reaction as the key steps. The combination of a second-generation Grubbs catalyst and microwave irradiation proved to be highly useful in generating the otherwise difficult to obtain medium-sized ring system of the buflavine analogues.
Appukkuttan
Prasad
P
Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium.
Dehaen
Wim
W
Van der Eycken
Erik
E