3-(4-Hydroxyphenyl)-5,7-dihydroxy-6-(3-methyl-2-butenyl)-4H-1-benzopyran-4-one synthesis

Yield:-

Steps:

Multi-step reaction with 5 steps
1: 81 percent / pyridine / 20 °C
2: 53 percent / PPh₃; DEAD / tetrahydrofuran / 0 - 20 °C
3: 57 percent / Eu(fod)3 / CHCl₃ / 18 h / 85 °C / sealed tube
4: 86 percent / (1,3-dimesitylimidazolidin-2-yl)(PCy₃)benzylidene-RuCl₂ / benzene / 72 h / 20 °C / sealed tube
5: 91 percent / K₂CO₃ / methanol / 2 h / 40 °C

References:

Tischer, Sandra;Metz, Peter [Advanced Synthesis and Catalysis,2007,vol. 349,# 1-2,p. 147 - 151]