The Photodecarbonylation of α‐Aryl Aldehydes: 1‐Formyl‐1‐methyl‐indan and heterocyclic analogues

Indoline‐3‐Carboxylic Acid Derived Organocatalysts for the anti‐Mannich Reaction

“…The residue was purified by filter flash chromatography (petroleum ether/ethyl acetate 95:5) and 17 was obtained in 95 % yield (2.81 g, 10.21 mmol) as a colourless powder. Spectroscopic data are full in agreement with those reported in literature 29. M.p.…”

“…Subsequent filter flash chromatography (petroleum ether/ethyl acetate 95:5) afforded 18 as colourless oil in 93 % yield (2.95 g, 10.6 mmol). Spectroscopic data are full in agreement with those reported in literature 29 . 1 H NMR (600 MHz, CDCl 3 ): δ =1.57 (s, 9 H, C(Me) 3 ), 3.78 (s, 3 H, OMe), 4.10 (br s, 1 H, 2‐H a ), 4.21 (dd, J =5.9 Hz, J =6.5 Hz, 1 H, 3‐H), 4.39 (br s, 1 H, 2‐H b ), 6.96 (dt, J =1.1, 7.5 Hz, 1 H, arom.‐H), 7.23 (t, J =7.7 Hz, 1 H, arom.‐H), 7.35 (d, J =7.6 Hz, 1 H, arom.‐H), 7.88 ppm (br s, 1 H, arom.‐H); 13 C NMR (151 MHz, CDCl 3 ): δ =28.5 (C( Me ) 3 ), 49.8 (C‐2), 52.6 (COO Me ), 81.0 ( C (Me) 3 ), 115.0, 122.3, 125.1 (arom.‐CH), 129.0 (arom.‐C ipso ), 142.7 (arom.‐C ipso ), 152.1 (N C O), 171.9 ppm (COO Me ); IR (ATR film): $\tilde \nu $ =2977, 1739 (NCO), 1698 (CO), 1485, 1390, 1166, 1131, 1014 cm −1 ; GC‐MS (EI, 70 eV): m / z (%): 176 (25) [C 10 H 10 NO 2 + ], 118 (100) [C 8 H 8 N + ]; elemental analysis calcd (%) for C 15 H 19 NO 4 (277.32): C 64.97, H 6.91, N 5.05; found: C 64.75, H 7.04, N 4.76.…”

“…After filtration and concentration under reduced pressure, the residue was purified by filter flash chromatography (petroleum ether/ethyl acetate 80:20) to give rac ‐ 19 in 97 % yield (1.36 g, 7.67 mmol) as yellow–brownish oil. Spectroscopic data are full in agreement with those reported in literature 29 . 1 H NMR (600 MHz, CDCl 3 ): δ =3.75 (dd, J =9.6, 9.6 Hz, 1 H, 2‐H a ), 3.77 (s, 3 H, COOMe), 3.94 (dd, J =9.6, 7.5 Hz, 1 H, 2‐H b ), 4.20 (dd, J =9.6, 7.5 Hz, 1 H, 3‐H), 6.67 (d, J =7.8 Hz, 1 H, arom.‐H), 6.75 (dt, J =1.0, 7.5 Hz, 1 H, arom.‐H), 7.09 (m, 1 H, arom.‐H), 7.30 ppm (ddt, J =0.6, 1.2, 7.5 Hz, 1 H, arom.‐H); 13 C NMR (151 MHz, CDCl 3 ): δ =47.2 (C‐3), 49.3 (C‐2), 52.3 (COO Me ), 110.1, 119.0, 125.2 (arom.‐CH), 126.0 (arom.‐C ipso ), 128.8 (arom.‐CH), 151.1 (arom.‐C ipso ), 172.7 ppm (CO); IR (ATR film): $\tilde \nu $ =3376 (NH), 2951, 2881, 1727 (CO), 1604, 1488, 1464, 1434, 1316, 1251, 1196, 1170, 1019, 745 cm −1 ; GC‐MS (EI, 70 eV): m / z (%): 177 (28) [ M + ], 118 (100) [C 8 H 8 N + ].…”

“…1‐ tert ‐Butyl‐3‐methyl‐1 H ‐indole‐3‐carboxylate (17) : According to the literature procedure,29 16 (1.87 g, 10.7 mmol) was dissolved in THF (50 mL) and cooled to 0 °C, before NaH (333 mg, 13.9 mmol) was added. After effervescence had ceased, Boc 2 O (3.03 g, 13.9 mmol) was added in one portion, under vigorous stirring, whereupon a precipitate was formed.…”

“…M.p. 127.0 °C (125–127 °C)29; 1 H NMR (600 MHz, CDCl 3 ): δ =1.69 (s, 9 H, C(Me) 3 ), 3.94 (s, 3 H, OMe), 7.33–7.39 (m, 2 H, arom.‐H), 8.16 (m, 1 H, arom.‐H), 8.17 (br s, 1 H, arom.‐H), 8.27 ppm (s, 1 H, 2‐H); 13 C NMR (151 MHz, CDCl 3 ): δ =28.1 (C( Me ) 3 ), 51.5 (COO Me ), 85.1 ( C (Me) 3 ), 112.2 (C‐3), 115.2, 121.7, 124.0, 125.1 (arom.‐CH), 127.5 (C‐2), 132.0 (arom.‐C ipso ), 135.6 (arom.‐C ipso ), 149.0 (N C O), 164.7 ppm ( C OOMe); IR (attenuated total reflectance (ATR) film): $\tilde \nu $ =3170, 2977, 2948, 1811, 1743 (NCO), 1707 (CO), 1557, 1451, 1367, 1244, 2241, 739 cm −1 ; GC‐MS (EI, 70 eV): m / z (%): 175 (39) [C 10 H 8 NO 2 + ], 144 (100) [C 9 H 6 NO + ], 116 (20) [C 8 H 6 N + ]; elemental analysis calcd (%) for C 15 H 17 NO 4 (275.30): C 65.44, H 6.22, N 5.09; found: C 65.30, H 6.19, N 4.92.…”