Negishi Cross-Coupling Reaction as a Route to Isocombretastatins
摘要:
A series of isocombretastatins A has been synthesized by a new method based on the Negishi cross-coupling reaction in 19-84% yields. Five of the synthesized compounds exhibit high cytotoxic activity in nanomolar concentrations (IC50 = 1-100 nM) towards Jurkat, K562, Colo357, and A549 cell lines.
Expeditious synthesis of 1,1-diarylethylenes related to isocombretastatin A-4 (isoCA-4) via palladium-catalyzed arylation of N-tosylhydrazones with aryl triflates
A quick and efficient entry to 1,1-diarylethylenes via the reaction of polyoxygenated aryl N-tosylhydrazones with aryl triflates is described. The reaction employs the catalytic system Pd(OAc)2/XPhos, tBuOLi as the base and dioxane as the solvent. A variety of substituents on both the coupling partners’ hydrazones and triflates are tolerated. This procedure provides a complementary route to the existing