1024
Helvetica Chimica Acta – Vol. 90 (2007)
1212s, 1163m, 1130m, 1063m. EI-MS: 178 (56), 149 (100), 121 (25), 103 (1), 91 (6), 79 (6), 63 (14), 51
(12), 42 (8).
3,4-Dihydro-3-oxo-2H-1,5-benzodioxepine-7-carboxaldehyde (16). As described in Exper. 3, with
11e (0.17 g, 0.68 mmol). Extraction was performed without NaHCO3 neutralization: yellow oily 16
(0.11 g, 85%). The sample was purified by semi-prep. HPLC (tR 7.8 min, lmax 270 nm): 16 (12 mg, 11%).
Yellow semi-solid. IR (KBr): 3437 (br.), 3041w, 2923w, 2852w, 2836w, 2735w, 1802w, 1736s, 1704w, 1683s,
1605w, 1575s, 1508m, 1438w, 1421w, 1383w, 1359w, 1341w, 1314m, 1299m, 1283s, 1269s, 1236w, 1208w,
1162w, 1109w, 1044m, 1027w, 1017w. 1H-NMR (300 MHz, CDCl3): 9.85 (s, CHO); 7.53 – 7.50 (m,
HꢀC(6), HꢀC(8)); 7.10 (d, J ¼ 8.8, HꢀC(9)); 4.79 (s, CH2(2)); 4.71 (s, CH2(4)). 13C-NMR (75 MHz,
CDCl3): 203.0 (C(3)); 190.2 (CHO); 153.5 (C(9a)); 148.6 (C(5a)); 132.4 (C(7)); 126.0 (C(8)); 122.7
(C(9)); 121.6 (C(6)); 76.1 (C(2)); 75.2 (C(4)). EI-MS: 192 (100, Mþ), 163 (81), 149 (6), 135 (13), 121 (5),
108 (15), 91 (4), 79 (26), 63 (12), 51 (19), 42 (6), 39 (5).
14. Preparation of 16 by Procedure B. 3,4-Dihydro-3-[(tetrahydro-2H-pyran-2-yl)oxy]-2H-1,5-
benzodioxepine-7-carboxaldehyde (26e). As described in Exper. 4, with 9e (0.50 g, 3.62 mmol): 26e
(0.74 g, 74%). Caramel brown viscous oil. IR (neat): 3422 (br.), 3063w, 2943m, 2869m, 2733w, 1803w,
1686s, 1601s, 1573m, 1501s, 1432m, 1389w, 1356w, 1316m, 1281s, 1201w, 1158m, 1127s, 1074s, 1033s.
1H-NMR (300 MHz, CDCl3): 9.77 (s, CHO); 7.42 – 6.95 (m, HꢀC(6), HꢀC(8), HꢀC(9)); 4.72 (ꢀtꢁ,
HꢀC(2’)); 4.59 – 4.22 (m, CH2(4), HꢀC(3), CH2(2)); 4.01 – 3.78 (m, HaꢀC(6’)); 3.56 – 3.51 (m,
HbꢀC(6’)); 1.80 – 1.18 (m, CH2(5’), CH2(4’), CH2(3’)). 13C-NMR (75 MHz, CDCl3): 190.6 (CHO); 155.3
(C(9a)); 150.1 (C(5a)); 131.7 (C(7)); 125.2 (C(8)); 121.4 (C(9)); 121.3 (C(6)); 98.7 (C(2’)); 74.0 (C(3));
72.9 (C(2)); 72.0 (C(4)); 62.8 (C(6’)); 30.7 (C(3’)); 25.2 (C(5’)); 19.5 (C(4’)). EI-MS: 278 (22, Mþ), 250
(1), 222 (2), 194 (30), 176 (19), 164 (16), 149 (30), 137 (4), 121 (3), 119 (4), 113 (3), 109 (2), 105 (1), 103
(1), 99 (1), 93 (1), 91 (5), 85 (100), 79 (5), 67 (13), 57.1 (14), 55 (7), 51 (3).
3,4-Dihydro-3-hydroxy-2H-1,5-benzodioxepine-7-carboxaldehdye (27e). As described in Exper. 4,
with 26e (0.56 g, 2.01 mmol): 27e (0.35 g, 89%). Yellow resin. IR (neat): 3440 (br.), 3078w, 2939m,
2856m, 2735w, 2620w, 1794w, 1731m, 1688s, 1599s, 1588m, 1574m, 1505s, 1434s, 1394w, 1359w, 1338w,
1317m, 1280s, 1169m, 1138m, 1099w, 1035m. 1H-NMR (300 MHz, CDCl3): 9.82 (s, CHO); 7.47 – 7.45 (m,
HꢀC(6), HꢀC(8)); 7.06 (d, J ¼ 8.8, HꢀC(9)); 4.32 – 4.14 (m, CH2(2), HꢀC(3), CH2(4)); 2.87 (br. s,
OH). 13C-NMR (75 MHz, CDCl3): 190.6 (CHO); 155.8 (C(9a)); 150.8 (C(5a)); 132.2 (C(7)); 125.7
(C(8)); 122.6 (C(9)); 121.8 (C(6)); 74.7 (C(2)); 74.5 (C(4)); 69.1 (C(3)). EI-MS: 194 (100, Mþ), 175 (3),
163 (17), 149 (65), 137 (21), 121 (13), 119 (6), 109 (6), 105 (3), 95 (6), 91 (5), 79 (8), 77 (8), 65 (9), 63
(11), 57 (7), 51 (9).
3,4-Dihydro-3-oxo-2H-1,5-benzodioxepine-7-carboxaldehyde (16). As described in Exper. 4, with
27e (0.25 g, 1.29 mmol). The crude resin was crystallized from MeCN: 16 (0.13 g, 52%). White solid. M.p.
(MeCN) 110 – 1128.
15. Benzodioxepinone 17 by Procedure A. 2,2’-{[4-(tert-Butyl)-1,2-phenylene]bis(oxy)}bis[acetic
Acid] Dimethyl Ester (10f). As described in Exper. 3 (conventional method), with 9f (1.00 g, 6.02 mmol).
Bulb-to-bulb distillation (1908/0.3 Torr) performed twice afforded 10f (1.40 g, 75%). Clear oil. IR (neat):
2908s, 2956s, 2870m, 2111w, 1762s, 1608m, 1592m, 1583m, 1510s, 1440s, 1414m, 1376m, 1364m, 1294s,
1201s, 1153s, 1110m, 1068s, 1028m, 1005m. 1H-NMR (300 MHz, CDCl3)1): 6.96 – 6.77 (m, HꢀC(3’),
t
HꢀC(5’), HꢀC(6’)); 4.72 (s, CH2(1’’)); 4.68 (s, CH2(2)); 3.78 (s, Me(3)O, Me(3’’)O); 1.26 (s, Bu).
13C-NMR (75 MHz, CDCl3)1): 169.5 (CO(1), CO(2’’)); 147.3 (C(1’)); 145.9 (C(2’), C(4’)); 119.4 (C(5’));
114.9 (C(6’)); 114.2 (C(3’)); 67.2 (CH2(2)); 66.7 (CH2(1’’)); 52.1 (Me(3)O); 52.0 (Me(3’’)O); 34.3
(Me3C); 31.3 (Me3C). EI-MS: 310 (23, Mþ), 295 (100), 222 (2), 205 (1), 191 (1), 177 (4), 163 (11), 149
(3), 133 (5), 121 (2), 117 (2), 105 (4), 91 (6), 77 (5), 65 (2), 59 (2), 51 (1), 45 (32).
Methyl 7-(tert-Butyl)-3,4-dihydro-3-oxo- and 8-(tert-Butyl)-3,4-dihydro-3-oxo-2H-1,5-benzodioxe-
pine-2-carboxylate (11f). As described in Exper. 3, with 10f (2.42 g, 7.81 mmol): 11f (1.89 g, 87%). Clear
brown oil. IR (neat): 3456m, 2958s, 2870s, 2566m, 2085w, 1741s, 1582m, 1504s, 1473m, 1437s, 1414s,
1364m, 1269s, 1206s, 1149s, 1126s, 1102m, 1079m. 1H-NMR (300 MHz, CDCl3): Regioisomer 1: 7.11 – 6.94
(m, HꢀC(6), HꢀC(8), HꢀC(9)); 5.40 (s, HꢀC(2)); 4.82 (d, J ¼ 16.4, HaꢀC(4)); 4.60 (d, J ¼ 16.6,
HbꢀC(4)); 3.87 (s, MeO); 1.28 (s, tBu); Regioisomer 2: 7.11 – 6.94 (m, HꢀC(6), HꢀC(8), HꢀC(9)); 5.36
t
(s, HꢀC(2)); 4.81 (d, J ¼ 17.1, HaꢀC(4)); 4.58 (d, J ¼ 16.8, HbꢀC(4)); 3.86 (s, MeO); 1.28 (s, Bu).
13C-NMR (75 MHz, CDCl3): Regioisomer 1: 199.6 (C(3)); 165.5 (CO2); 148.5 (C(9a)); 146.4 (C(5a));