The synthesis of 4-ethyl-5-methyl-5,6-dihydro-phenanthridine-8,9-diol as the key intermediate of a series of potent Wnt signalling pathway agonists is reported. This synthesis features a consecutive aryl-aryl and N-aryl coupling, leading to 4-ethyl-5-methyl-8,9-dimethoxyphenanthridin-6-(5H)-one, whose structure was determined by spectroscopic analysis and X-ray crystallography, in a one-pot sequence with the presence of palladium catalyst and TFP (tri(2-furyl)phosphine) as the ligand.
