*(1E,6E)-1,7-bis(4-Hydroxy-3-methoxyphenyl)-4,4-di(prop-2-yn-1-yl)hepta-1,6-diene-3,5-dione* (**5m**)

Yield: 83%; mp = 201–203 ◦C; 1H-NMR (CDCl3) δ 7.75 (d, *J* = 15.0 Hz, 2H), 7.13 (dd, *J* = 8.0, 1.5 Hz, 2H), 7.03 (d, *J* = 2.0 Hz, 2H), 6.92 (d, *J* = 8.0 Hz, 2H), 6.67 (d, *J* = 15.0 Hz, 2H), 5.97 (s, 2H), 3.95 (s, 6H), 3.19 (s, 4H), 2.04 (s, 4H); 13C-NMR (CDCl3) δ 193.5, 148.9, 145.9, 126.5, 124.7, 117.8, 114.8, 109.8, 79.1, 71.9, 66.9, 56.1, 21.2; HRMS [ESI]<sup>+</sup> calculated for C27H28O6: 471.1784 [M + Na]+; found: 471.1783.
