3.4.1. (E)-3-((E)-1,3-Diphenylallylidene)-1-methylindolin-2-one (**3aa**)

84% Yield; yellow solid; mp = 125.7 ◦C; *<sup>R</sup>*<sup>f</sup> = 0.4 (silica gel, hexane:EtOAc = 4:1); 1H NMR (500 MHz, CDCl3): *<sup>δ</sup>* 9.38 (d, *<sup>J</sup>* = 16.0 Hz, 1H), 7.55–7.51 (m, 5H), 7.33–7.25 (m, 5H), 7.08 (td, *J* = 8.2, 7.6 Hz, 1H), 6.74 (d, *J* = 7.8 Hz, 1H), 6.60 (t, *J* = 7.7 Hz, 1H), 6.47 (d, *J* = 16.0 Hz, 1H), 5.72 (d, *J* = 7.8 Hz, 1H), 3.3 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3): *δ* 168.1, 151.2, 142.9, 141.6, 137.8, 136.9, 129.3, 129.2, 128.8, 128.7, 128.6, 128.3, 128.0, 127.7, 123.7, 123.4, 122.6, 121.6, 107.6, 25.9 ppm; HRMS (EI): calcd for C24H19NO [M+]: 337.1467, found 337.1466.
