3.3.1. (Z)-2-(1-Methyl-2-oxoindolin-3-ylidene)-2-phenylacetaldehyde (**7a**) [23]

84% Yield; orange solid; mp = 187.8–190.7 ◦C (lit. [23] 174-176 ◦C); *R*<sup>f</sup> = 0.35 (silica gel, hexanes:EtOAc = 3:1); 1H NMR (500 MHz, CDCl3): *δ* 11.40 (s, 1H), 7.49 (dd, *J* = 3.7, 2.7 Hz, 3H), 7.28–7.19 (m, 3H), 6.77 (d, *J* = 7.8 Hz, 1H), 6.68 (td, *J* = 7.7, 0.9 Hz, 1H), 6.26 (d, *J* = 7.7 Hz, 1H), 3.25 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3) *δ* 193.3, 167.3, 145.8, 145.6, 135.5, 133.3, 132.2, 129.4, 129.2, 128.9, 126.2, 122.6, 121.4, 108.6, 26.2 ppm; HRMS (EI): calcd for C17H13NO2 [M+] : 263.0946, found 263.0942.

#### 3.3.2. (Z)-2-(4-Chlorophenyl)-2-(1-methyl-2-oxoindolin-3-ylidene)acetaldehyde (**7b**)

85% Yield; orange solid; mp = 186.8–189.1 ◦C; *<sup>R</sup>*<sup>f</sup> = 0.32 (silica gel, hexane:EtOAc = 3:1); 1H NMR (500 MHz, CDCl3): *<sup>δ</sup>* 11.38 (s, 1H), 7.52–7.45 (m, 2H), 7.29 (td, *<sup>J</sup>* = 7.8, 1.1 Hz, 1H), 7.20–7.16 (m, 2H), 6.79 (d, *J* = 7.8 Hz, 1H), 6.74 (td, *J* = 7.7, 0.9 Hz, 1H), 6.36 (d, *J* = 7.4 Hz, 1H), 3.27 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3) *δ* 192.9, 167.1, 145.7, 144.4, 135.9, 135.6, 132.6, 131.6, 130.6, 129.6, 126.1, 122.7, 121.1, 108.8, 26.3 ppm; HRMS (EI): calcd for C17H12ClNO2 [M+] : 297.0557, found 297.0556.

## 3.3.3. (Z)-2-(1-Methyl-2-oxoindolin-3-ylidene)-2-(4-nitrophenyl)acetaldehyde (**7c**)

87% Yield; red solid; mp = 194.2–196.8 ◦C; *R*<sup>f</sup> = 0.34 (silica gel, hexane:EtOAc = 4:1); 1H NMR (500 MHz, CDCl3): *δ* 11.41 (s, 1H), 8.36 (d, *J* = 8.5 Hz, 2H), 7.43 (d, *J* = 8.5 Hz, 2H), 7.31 (t, *J* = 7.7 Hz, 1H), 6.81 (d, *J* = 7.8 Hz, 1H), 6.71 (t, *J* = 7.7 Hz, 1H), 6.20 (d, *J* = 7.7 Hz, 1H), 3.27 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3) *δ* 192.1, 166.8, 148.4, 146.1, 142.9, 140.2, 136.4, 133.2, 130.4, 126.1, 124.4, 122.9, 120.6, 109.1, 26.3 ppm; HRMS (EI): calcd for C17H12N2O4 [M+] : 308.0797, found 308.0797.

#### 3.3.4. (Z)-2-(4-Iodophenyl)-2-(1-methyl-2-oxoindolin-3-ylidene)acetaldehyde (**7e**)

78% Yield; orange solid; mp = 157.2–159.5 ◦C; *<sup>R</sup>*<sup>f</sup> = 0.20 (silica gel, hexane:EtOAc = 3:1); 1H NMR (500 MHz, CDCl3): *<sup>δ</sup>* 11.36 (s, 1H), 7.83 (d, *<sup>J</sup>* = 8.2 Hz, 2H), 7.29 (td, *<sup>J</sup>* = 7.8, 0.8 Hz, 1H), 6.98 (d, *J* = 8.2 Hz, 2H), 6.78 (d, *J* = 7.8 Hz, 1H), 6.74 (t, *J* = 7.7 Hz, 1H), 6.38 (d, *J* = 7.7 Hz, 1H), 3.25 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3) *δ* 192.7, 167.0, 145.7, 144.3, 138.3, 135.7, 132.7, 132.6, 130.9, 126.1, 122.7, 121.0, 108.7, 95.7, 26.2 ppm; HRMS (EI): calcd for C17H12INO2 [M+] : 388.9913, found 388.9908.
