Supplementary Figure S1. Single X-ray structure 3a at probability ellipsoids of 20%.

Supplementary Figure S1. Single X-ray structure 3a at probability ellipsoids of 20%. S1

Supplementary Figure S2. Single X-ray structure 5a at probability ellipsoids of 20%. S2

H 15 Ph Ac Ac I AcH Ph Ac 12 Isolated Ph Ph H TMS 20 mol% CHCl 3, 1 h retro-michael (retro-friedel-crafts) bond energy C- > C-C > C-Br Ac H 13 + 14 Ph Supplementary Figure S3. Preparation of the stable p-acetoxy quinol 12 and catalyst I catalyzed retro-michael addition reaction of 12. S3

Supplementary Figure S4. Monitoring quinol formation by 1 H MR. S4

Supplementary Table S1. Screening of Catalysts for the cascade reactions using enal 1a and 3- bromoindole 4a 2 H Br Catalyst 20 mol % TEA 1.2 equiv. CH 2 Cl 2, r.t. H 1a, 1.0 equiv. 2a, 2.0 equiv. 3a 2 H IX Entry Catatlyst t Yield E/Z (a) 1 I 6D 0% 2 II 6D 0% D (b) D 3 III 5D 27% 81:19 4 IV 5D 25% 98:2 5 V 6D 6% D 6 VI 3D 52% >99:1 7 VII 6D 9% D 8 VIII 5D 38% 98:2 9 IX 5D 21% 98:2 10 i-prh 8D <5% - Unless specified, the reaction was carried out with 0.1 mmol 1a and 0.2 mmol 2a in the presence of 20 mol % organocatalyst in 0.5 ml of DCM at r.t. (a) E/Z was determined by 1 H MR of crude reaction mixture. (b) ot determined. S5

Supplementary Table S2. Effect of additives and solvents on the synthesis of (E)-α-indolyl-βarylacrylaldehyde 5a Br Cat. VI 20 mol % 2 H 1a, 1.0 equiv. 2, 2.0 equiv. Additive, Solvent Temperature H 3a E/Z >99:1 2 Entry Solvent Additive T t Yield 1 CH 2 Cl 2 2,6-Lutidine, 1.2 eq. r.t. 5D 46% 2 CH 2 Cl 2 aac, 1.2 eq. r.t. 3D 62% 3 CH 2 Cl 2 aac, 4 eq. r.t. 3D 73% 4 CH 2 Cl 2 ahc 3, 4 eq. r.t. 3D 66% 5 CH 2 Cl 2 a 2 C 3, 4 eq. r.t. 3D 71% 6 CHCl 3 aac, 4 eq. r.t. 3D 81% 7 MeH aac, 4 eq. r.t. 3D 79% 8 MeC aac, 4 eq. r.t. 3D 52% 9 THF aac, 4 eq. r.t. 3D 73% 10 Toluene aac, 4 eq. r.t. 3D 78% 11 Et 2 aac, 4 eq. r.t. 3D 66% 12 DMF aac, 4 eq. r.t. 3D 59% 13 Acetone aac, 4 eq. r.t. 3D 77% 14 CHCl 3 aac, 4 eq. 60 C 7h 89% 15 CHCl 3 aac, 4 eq. 60 C 22h 90% Unless specified, the reaction was carried out with 0.1 mmol 1a and 0.2 mmol 2 in the presence of 20 mol % organocatalyst VI in 0.5 ml of solvent at the designated temperature. (a) E/Z was determined by proton MR of crude reaction mixture. S6

Supplementary Methods Me 3l H (E)-2-(4-Hydroxyphenyl)-3-(2-methoxyphenyl)acrylaldehyde (3l) (Table 2, entry 12). The title compound was prepared according to the typical procedure, as described above in 52% yield. M. P. 173-174 ºC; 1 H MR (acetone-d 6, 500 MHz): δ = 9.76 (s, 1H), 8.47 (br, 1H), 7.74 (s, 1H), 7.30 (t, J = 7.8 Hz, 1H), 7.06 (d, J = 8.0 Hz, 1H), 7.00 (d, J = 8.5 Hz, 2H), 6.97 (d, J = 7.5 Hz, 1H), 6.82 (d, J = 8.5 Hz, 2H), 6.68 (t, J = 7.5 Hz, 1H), 3.91 (s, 3H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.3, 159.0, 158.0, 144.5, 142.1, 132.1, 131.6, 130.8, 125.4, 124.1, 120.6, 116.0, 111.9, 56.0; HRMS (ESI) calcd. for C 16 H 14 3 : m/z 277.0841 ([M + a] + ), found 277.0835. 3m H (E)-2-(4-Hydroxyphenyl)-3-o-tolylacrylaldehyde (3m) (Table 2, entry 13). The title compound was prepared according to the typical procedure, as described above in 50% yield. M. P. 161-162 ºC; 1 H MR (acetone-d 6, 500 MHz): δ = 9.83 (s, 1H), 8.45 (br, 1H), 7.69 (s, 1H), 7.19 (d, J = 5.0 Hz, 1H), 7.17 (m, 1H), 6.95 (m. 4H), 6.76 (d, J = 8.5 Hz, 2H), 2.40 (s, 3H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.5, 158.0, 148.5, 143.1, 138.3, 134.9, 131.9, 131.0, 130.0, 129.8, 126.1, 124.8, 115.8, 19.9; HRMS (ESI) calcd. for C 16 H 14 2 : m/z 261.0891 ([M + a] + ), found 261.0889. H 3n (E)-3-(Furan-2-yl)-2-(4-hydroxyphenyl)acrylaldehyde (3n) (Table 2, entry 14). The title compound was prepared according to the typical procedure, as described above in 46% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.68 (s, 1H), 8.55 (br, 1H), 7.68 (s, 1H), 7.36 (s, 1H), 7.06 (d, J = 8.0 Hz, 2H), 6.90 (d, J = 8.5 Hz, 2H), 6.50 (d, J = 2.0 Hz, 1H), 6.34 (d, J = 3.5 Hz, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 193.2, 158.2, 151.8, 146.3, 139.5, 135.9, 131.3, 130.8, 125.3, 116.6, 116.0, 113.4; HRMS (ESI) calcd. for C 13 H 10 3 : m/z 237.0528 ([M + a] + ), found 237.0525. S7

3o H (E)-2-(4-Hydroxyphenyl)-3-(naphthalen-2-yl)acrylaldehyde (30) (Table 2, entry 15). The title compound was prepared according to the typical procedure, as described above in 84% yield. M. P. 151-152 ºC; 1 H MR (acetone-d 6, 500 MHz): δ = 9.81 (s, 1H), 8.62 (br, 1H), 7.98 (s, 1H), 7.84 (d, J = 7.5 Hz, 1H), 7.80 (d, J = 8.0 Hz, 1H), 7.69 (m, 2H), 7.51 (m, 2H), 7.27 (d, J = 8.5 Hz, 1H), 7.06 (d, J = 8.5 Hz, 2H), 6.89 (d, J = 8.5 Hz, 2H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.3, 158.2, 149.7, 142.7, 134.4, 133.8, 133.2, 132.3, 131.6, 129.2, 128.3, 128.2, 128.1, 127.2, 127.1, 125.1, 116.1; HRMS (ESI) calcd. for C 19 H 14 2 : m/z 297.0891 ([M + a] + ), found 297.0890. 3p H (E)-2-(4-Hydroxyphenyl)-3-(naphthalen-1-yl)acrylaldehyde (3p) (Table 2, entry 16). The title compound was prepared according to the typical procedure, as described above in 68% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 10.00 (s, 1H), 8.45 (br, 1H), 8.25 (d, J = 8.5 Hz, 1H), 8.20 (s, 1H), 7.95 (d, J = 7.5 Hz, 1H), 7.87 (d, J = 8.0 Hz, 1H), 7.58 (m, 2H), 7.30 (t, J = 7.8 Hz, 1H), 7.22 (d, J = 7.5 Hz, 1H), 6.97 (d, J = 8.5 Hz, 2H), 6.72 (d, J = 8.5 Hz, 2H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.5, 157.9, 147.6,144.3, 134.4, 132.9, 132.4, 131.9, 130.9, 130.1, 129.4, 128.5, 127.5, 127.0, 125.8, 124.7, 115.8; HRMS (ESI) calcd. for C 19 H 14 2 : m/z 297.0891 ([M + a] + ), found 297.0884. Me 3r H (E)-2-(4-Hydroxy-3-methoxyphenyl)-3-phenylacrylaldehyde (3r) (Table 2, entry 18). The title compound was prepared according to the typical procedure, as described above in 99% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.75 (s, 1H), 7.79 (br, 1H), 7.51 (s, 1H), 7.31 (m, 5H), 6.86 (d, J = 8.0 Hz, 1H), 6.75 (s, 1H), 6.63 (d, J = 8.0 Hz, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.3, 149.7, 148.3, 147.4, 142.7, 135.4, 131.2, 130.5, 129.1, 125.5, 123.1, 116.0, 113.6, 56.1; HRMS (ESI) calcd. for C 16 H 14 3 : m/z 277.0841 ([M + a] + ), found 277.0837. H 3s S8

(E)-2-(4-Hydroxy-3,5-dimethylphenyl)-3-phenylacrylaldehyde (3s) (Table 2, entry 19). The title compound was prepared according to the typical procedure, as described above in 86% yield. M. P. 148-149 ºC; 1 H MR (acetone-d 6, 500 MHz): δ = 9.74 (s, 1H), 7.47 (s, 2H), 7.30 (m, 5H), 6.75 (s, 2H), 2.20 (s, 6H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.5, 153.9, 149.5, 142.9, 135.5, 131.2, 130.5, 129.9, 129.0, 125.3, 124.9, 16.4; HRMS (ESI) calcd. for C 17 H 16 2 : m/z 275.1048 ([M + a] + ), found 275.1046. H 3t (E)-2-(4-Hydroxy-2-methylphenyl)-3-phenylacrylaldehyde (3t) (Table 2, entry 20). The title compound was prepared according to the typical procedure, as described above in 91% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.77 (s, 1H), 8.40 (br, 1H), 7.29 (m, 6H), 6.80 (d, 2H), 6.72 (m, 1H), 1.95 (s, 3H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.4, 158.1, 150.6, 142.8, 138.2, 135.6, 131.0, 130.8, 129.3, 125.6, 117.7, 114.0, 19.6; HRMS (ESI) calcd. for C 16 H 14 2 : m/z 261.0891 ([M + a] + ), found 261.0891. F 3u H (E)-2-(3-Fluoro-4-hydroxyphenyl)-3-phenylacrylaldehyde (3u) (Table 2, entry 21). The title compound was prepared according to the typical procedure, as described above in 79% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.74 (s, 1H), 8.88 (br, 1H), 7.57 (s, 1H), 7.31 (m, 5H), 7.02 (t, J = 8.8 Hz, 1H), 6.94 (d, J = 12 Hz, 1H), 6.81 (d, J = 8.0 Hz, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 193.9, 153.0, 151.1, 150.4, 145.5, 145.4, 141.4, 135.1, 131.1, 130.7, 129.1, 126.6, 126.0 2, 118.6, 118.0, 117.8; HRMS (ESI) calcd. for C 15 H 11 F 2 : m/z 265.0641 ([M + a] + ), found 265.0635. Cl 3v H (E)-2-(3-Chloro-4-hydroxyphenyl)-3-phenylacrylaldehyde (3v) (Table 2, entry 22). The title compound was prepared according to the typical procedure, as described above in 62% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.75 (s, 1H), 9.05 (br, 1H), 7.58 (s, 1H), 7.32 (m, 6H), 7.18 (s, 1H), 7.04 (d, J = 8.5 Hz, 1H), 6.95 (d, J = 8.0 Hz, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.0, 153.6, 150.6, 141.2, 135.1, 131.6, 131.2, 130.8, 130.1, 129.2, 126.7, 121.0, 117.6; HRMS (ESI) calcd. for C 15 H 11 Cl 2 : m/z 281.0345 ([M + a] + ), found 281.0344. S9

Cl H 3w (E)-2-(2-Chloro-4-hydroxyphenyl)-3-phenylacrylaldehyde (3w) (Table 2, entry 23). The title compound was prepared according to the typical procedure, as described above in 62% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 9.76 (s, 1H), 7.72 (s, 1H), 7.33 (m, 6H), 7.02 (d, J = 2.5 Hz, 1H), 6.98 (d, J = 8.0 Hz, 1H), 6.87 (dd, J = 8.0, 2.5 Hz, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 193.4, 159.1, 151.1, 140.6, 135.2, 134.2, 132.6, 131.0, 129.4, 125.0, 117.1, 115.6; HRMS (ESI) calcd. for C 15 H 11 Cl 2 : m/z 281.0345 ([M + a] + ), found 281.0342. H 2 3x (E)-2-(2-Hydroxynaphthalen-1-yl)-3-(4-nitrophenyl)acrylaldehyde (3x). A mixture of 1- bromo-2-naphthol (0.1 mmol), trans-4-nitrocinnamaldehdye (0.2 mmol), catalyst I (0.02 mmol), and aac (0.4 mmol) in 0.5 ml of CH 3 C was stirred at 60 C for 3 d. The solvent was evaporated and the residue was purified by column chromatography, eluting with a mixture of ethyl acetate and hexane. 1 H MR (acetone-d 6, 500 MHz): δ = 9.98 (s, 1H), 8.76 (s, 1H), 8.13 (s, 1H), 8.02 (d, J = 8.5 Hz, 2H), 7.87 (m, 2H), 7.52 (d, J = 8.5 Hz, 2H), 7.42 (d, J = 8.0, 1H), 7.30 (m, 3H); 13 C MR (DMS-d 6, 125 MHz): δ = 194.5, 152.6, 148.8, 147.6, 140.9, 139.9, 132.0, 130.5, 130.1, 128.3, 127.9, 126.8, 123.6, 123.0, 122.9, 118.3, 112.2; HRMS (ESI) calcd. for C 19 H 13 4 : m/z 342.0742 ([M + a] + ), found 342.0739. H 5o (E)-2-(1H-Indol-3-yl)-3-(naphthalen-1-yl)acrylaldehyde (5o) (Table 3, entry 15). The title compound was prepared according to the typical procedure, as described above in 96% yield. 1 H MR (CDCl 3, 500 MHz): δ = 10.04 (s, 1H), 8.38 (br, 1H), 8.27 (d, J = 8.0 Hz, 1H), 8.11 (s, 1H), 7.89 (d, J = 8.0, 1H), 7.74 (d, J = 8.0, 1H), 7.64 (t, J = 7.5, 1H), 7.57 (t, J = 7.5, 1H), 7.47 (d, J = 2.5, 1H), 7.35-7.30 (m, 2H), 7.15-7.04 (m, 2H), 6.72-6.65 (m, 2H); 13 C MR (CDCl 3, 125 MHz): δ = 194.9, 145.9, 136.3, 136.1, 133.8, 132.3, 131.9, 130.1, 129.2, 128.0, 127.2, 126.7, 126.4, 125.4, 123.9, 122.6, 122.3, 121.1, 120.1, 111.4, 108.0; HRMS (ESI) calcd. for C 21 H 15 : m/z 320.1051 ([M + a] + ), found 320.1046. S10

2 5p H (E)-2-(2-Methyl-1H-indol-3-yl)-3-(4-nitrophenyl)acrylaldehyde (5p) (Table 3, entry 16). The title compound was prepared according to the typical procedure, as described above in 100% yield. 1 H MR (CDCl 3, 500 MHz): δ = 9.90 (s, 1H), 8.33 (br, 1H), 8.02 (d, J = 8.5 Hz, 2H), 7.60 (s, 1H), 7.45 (d, J = 8.5 Hz, 2H), 7.30 (d, J = 8.0 Hz, 1H), 7.13 (t, J = 7.0 Hz, 1H), 6.99 (m, 2H), 2.11 (s, 3H); 13 C MR (CDCl 3, 125 MHz): δ = 194.4, 147.9, 145.9, 141.6, 138.2, 136.1, 134.5, 130.9 2, 126.9, 123.9 2, 122.2, 120.6, 119.4, 111.1, 104.9, 13.2; HRMS (ESI) calcd. for C 18 H 14 2 3 : m/z 329.0902 ([M + a] + ), found 329.0900. 2 5q H (E)-3-(4-itrophenyl)-2-(2-phenyl-1H-indol-3-yl)acrylaldehyde (5q) (Table 3, entry 17). The title compound was prepared according to the typical procedure, as described above in 100% yield. 1 H MR (CDCl 3, 500 MHz): δ = 9.76 (s, 1H), 8.68 (br, 1H), 7.94 (d, J = 8.5, 2H), 7.66 (s, 1H), 7.42-7.34 (m, 5H), 7.27-7.25 (m, 3H), 7.20 (t, J = 7.5 Hz, 1H), 7.06-7.02 (m, 2H); 13 C MR (CDCl 3, 125 MHz): δ = 194.0, 147.9, 145.0, 141.4, 138.1, 137.1, 136.7, 132.3, 130.8 2, 129.3 2, 128.6, 127.3 2, 127.3, 123.8 2, 123.5, 121.1, 120.0, 111.8, 105.4; HRMS (ESI) calcd. for C 23 H 16 2 3 : m/z 391.1059 ([M + a] + ), found 391.1052. 2 H 5r 2 (E)-2-(5-itro-1H-indol-3-yl)-3-(4-nitrophenyl)acrylaldehyde (5r) (Table 3, entry 18). The title compound was prepared according to the typical procedure, as described above in 65% yield. 1 H MR (CDCl 3, 500 MHz): δ = 9.93 (s, 1H), 9.09 (br, 1H), 8.08-8.04 (m, 3H), 7.80 (d, J = 1.5 Hz, 1H), 7.61 (s, 1H), 7.59 (d, J = 2.5 Hz, 1H), 7.48 (d, J = 9.0 Hz, 2H), 7.45 (d, J = 9 Hz, 1H); 13 C MR (CDCl 3, 125 MHz): δ = 193.6, 148.2, 146.7, 142.5, 141.0, 139.3, 136.2, 130.9 2, 129.6, 124.6, 124.0 2, 118.6, 117.5, 112.1, 109.2; HRMS (ESI) calcd. for C 17 H 11 3 5 : m/z 360.0596 ([M + a] + ), found 360.0592. Br H 5s 2 S11

(E)-2-(5-Bromo-1H-indol-3-yl)-3-(4-nitrophenyl)acrylaldehyde (5s) (Table 3, entry 19). The title compound was prepared according the typical procedure, as described above in 100% yield. 1 H MR (acetone-d 6, 500 MHz): δ = 10.90 (br, 1H), 9.93 (s, 1H), 8.09 (d, J = 8.0 Hz, 2H), 7.75 (s, 1H), 7.64 (s, 1H), 7.63 (d, J = 8.0 Hz, 2H), 7.45 (d, J = 8.5 Hz, 1H), 7.19 (d, J = 8.5 Hz, 1H), 6.90 (s, 1H); 13 C MR (acetone-d 6, 125 MHz): δ = 194.5, 148.4, 145.4, 143.0, 137.8, 136.2, 131.7 2, 129.7, 127.6, 125.3, 124.2 2, 123.4, 114.5, 113.2, 106.7; HRMS (ESI) calcd. for C 17 H 11 Br 2 3 : m/z 392.9851 ([M + a] + ), found 392.9847. 2 Me Br 5t H (E)-2-(2-Bromo-5-methoxy-1H-indol-3-yl)-3-(4-nitrophenyl)acrylaldehyde (5t) (Table 3, entry 20). The title compound was prepared according to the typical procedure, as described above in 87% yield. 1 H MR (CDCl 3, 500 MHz): δ = 9.89 (s, 1H), 8.65 (br, 1H), 8.05 (d, J = 8.5 Hz, 2H), 7.70 (s, 1H), 7.45 ((d, J = 8.5 Hz, 2H), 7.21 (d, J = 9.0 Hz, 1H), 6.83 (dd, J = 9.0, 2.0 Hz, 1H), 6.47 (d, J = 2.0 Hz, 1H), 3.66 (s, 3H); 13 C MR (CDCl 3, 125 MHz): δ = 193.1, 155.2, 148.2, 146.9, 141.1, 136.4, 131.8, 131.0 2, 127.3, 124.0X2, 113.6, 112.2, 110.2, 108.5, 101.2, 55.9; HRMS (ESI) calcd. for C 18 H 13 Br 2 4 : m/z 422.9956 ([M + a] + ), found 422.9956. Preparation of -Boc protected 5m. Compound 5m (1 mmol) was dissolved in 5 ml of dry THF. 1.1 equiv. (1.1 mmol) di-tert-butyl dicarbonate, and 0.1 equiv. (0.1 mmol) 4- dimethylaminopyridine were added to the reaction mixture. After the indole was totally consumed (determined by TLC analysis), the solvent was evaporated and the residue was purified by column chromatography, eluting with a mixture of ethyl acetate and hexane to desired product in 100% yield. H 15 3-(4-Hydroxyphenyl)-3-phenylpropanal (15). The title compound was synthesized according to a known procedure. 56 1 H MR (CDCl 3, 500 MHz): δ = 9.73 (s, 1H), 7.37-7.18 (m, 5H), 7.09 (d, J = 9.0 Hz, 2H), 6.75 (d, J = 9.0 Hz, 2H), 4.62 (br, 1H), 4.56 (t, J = 8.0 Hz, 1H), 3.13 (dd, J 1 = 8.0, J 2 = 2.0 Hz, 2H). 12 S12

4-xo-1-(3-oxo-1-phenylpropyl)cyclohexa-2,5-dienyl acetate (12). The title compound was synthesized according to a known procedure. 57 (Diacetoxyiodo)benzene (0.5 mmol) was added to a solution of 3-(4-hydroxyphenyl)-3-phenylpropanal 15 (0.5 mmol) in glacial AcH (2.0 ml) at 0 C. After starting material was totally consumed, the reaction was concentrated and purified by flash chromatography. 1 H MR (CDCl 3, 500 MHz): δ = 9.60 (s, 1H), 7.30-7.18 (m, 5H), 6.73 (m, 2H), 6.31 (d, J = 10.0 Hz, 1H), 6.24 (d, J = 10.0 Hz, 1H), 3.81 (m, 1H), 2.95 (m, 2H), 2.10 (s, 3H). Supplementary References 56. Caschi, S., La Torre, F., Palmieri. G. The palladium-catalyzed conjugate addition type reaction of aryl iodides with α, β-unsaturated aldehydes. J. rganometat. Chem. 268, c48-c51 (1984). 57. Vo,. T., Pace, R. D. M., Hara, F. & Gaunt, M. J. An enantioselective organocatalytic oxidative dearomatization strategy. J. Am. Chem. Soc. 130, 404-405 (2008). S13