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5,7-Cyclo-2,2-dimethyl-benzo[c]-1,3-dioxolo[40,50:4,5]furo[2,3-
h]1,5-oxazonane (7a,b)
1H), 7.76 (d, J ¼ 8.1 Hz, 1H); dC (75 MHz, CDCl3) 21.6, 25.8, 26.5,
50.5, 65.6, 79.6, 84.1, 103.8, 111.3, 118.5, 122.4, 127.4, 127.6,
128.9, 129.1, 129.4, 129.7, 130.5, 132.6, 132.6, 136.5, 137.2,
144.0; IR nmax (lm): 3229, 2974, 2935, 1601, 1455, 1381, 1334,
1262, 1209, 1157, 1077, 1012, 939, 862, 814, 752, 661 cmꢂ1; MS
(EI) m/z 530, 532 (M + Na+ for Br79, Br81); found: C, 54.24; H,
5.12; N, 2.80. Calc. for C23H26BrNO5S: C, 54.63; H, 5.15; N,
2.75%.
White semi solid; yield 0.215 g (0.71 mmol, 71%); Rf ¼ 0.5 (eluent
PS–ethyl acetate 5 : 1); [a]D +29.8 (c 0.23, CHCl3); dH (300 MHz,
CDCl3) 1.34 (s, 3H), 1.49 (s, 3H), 2.09 (brs, 1H), 2.42 (d, J ¼
3.9 Hz, 1H), 2.58 (d, J ¼ 6.0 Hz, 1H), 4.24–4.28 (m, 1H), 4.63 (d, J
¼ 3.9 Hz, 1H), 4.68–4.73 (m, 2H), 5.02 (d, J ¼ 12.9 Hz, 1H), 5.98
(d, J ¼ 3.9 Hz, 1H), 6.76 (d, J ¼ 7.8 Hz, 1H), 6.93–6.98 (m, 1H),
7.11 (d, J ¼ 6.6 Hz, 1H), 7.20–7.23 (m, 1H); dC (75 MHz, CDCl3)
26.5, 27.3, 33.3, 44.9, 76.6, 77.4, 82.9, 85.5, 106.1, 111.8, 116.8,
122.6, 129.4, 129.7, 132.6, 153.6; IR nmax (lm): 2930, 2853, 2357,
1732, 1462, 1377, 1161, 1076, 1024 cmꢂ1; HRMS: (M + Na)+ for
N-(2-Bromo-benzyl)-(2,2-dimethyl-5-vinyl-tetrahydro-furo-[2,3-
d][1,3]-dioxol-6-yl)-carbamic acid benzyl ester (6b)
Thick oil; yield 0.336 g (0.69 mmol, 69%); Rf ¼ 0.67 (eluent PS–
ethyl acetate 13 : 1); [a]D ꢂ23.3 (c 0.29, CHCl3); dH (300 MHz,
CDCl3) 1.22 (s, 3H), 1.40 (s, 3H), 4.40 (d, J ¼ 15.3 Hz, 1H), 4.60–
4.72 (m, 3H), 4.88 (s, 1H), 5.17 (brs, 2H), 5.29 (d, J ¼ 10.5 Hz,
1H), 5.51 (d, J ¼ 14.7 Hz, 1H), 5.79–5.92 (m, 2H), 7.13–7.18 (m,
3H), 7.20–7.50 (m, 5H), 7.56 (d, J ¼ 7.8 Hz, 1H); dC (75 MHz,
CDCl3) 26.0, 26.7, 50.8, 67.5, 81.2, 83.6, 96.1, 105.0, 111.0, 118.6,
122.1, 127.5, 127.6, 128.4, 128.6, 131.6, 132.8, 136.0, 136.8,
156.3; IR nmax (lm): 2985, 2929, 1706, 1448, 1413, 1376, 1253,
1164, 1073, 1026, 931, 747 cmꢂ1; MS (EI) m/z 488, 490 (M+H+ for
Br79, Br81); found: C, 58.98; H, 5.40; N, 2.82. Calc. for
C
16H19NO4Na: calc. 312.1212, found: 312.1206.
5-Methoxy-5,7-cyclo-2,2-dimethyl-benzo[c]-1,3-dioxolo-
[40,50:4,5]furo[2,3-h]1,5-oxazonane (7c)
Yellowish white semisolid; yield 0.213 g (0.64 mmol, 64%); Rf ¼
0.5 (eluent PS–ethyl acetate 5 : 1); [a]D +32.9 (c 0.78, CHCl3); dH
(300 MHz, CDCl3) 1.34 (s, 3H), 1.49 (s, 3H), 1.96–2.05 (m, 1H),
2.38 (d-like, 1H), 2.53 (d, J ¼ 5.7 Hz, 1H), 3.75 (s, 3H), 4.23 (brs,
1H), 4.61–4.72 (m, 3H), 4.96 (d, J ¼ 12.6 Hz, 1H), 5.98 (d, J ¼
3.6 Hz, 1H), 6.65–6.76 (m, 3H); dC (75 MHz, CDCl3) 26.5, 27.3,
29.7, 33.4, 55.6, 68.7, 77.4, 83.1, 85.4, 106.1, 111.8, 113.2, 116.4,
125.0, 129.2, 133.6, 155.1; IR nmax (lm): 2923, 2854, 1734, 1498,
1462, 1376, 1262, 1164,1079, 1028, 859 cmꢂ1; HRMS: (M + Na)+
for C17H21NO5Na: calc. 342.1318, found: 342.1313.
C
24H26BrNO5: C, 58.72; H, 5.37; N, 2.87%.
(5-Bromo-benzo-[1,3]-dioxol-4-methyl)-(2,2-dimethyl-5-vinyl-
tetrahydro-furo-[2,3-d] [1,3]-dioxol-6-yl)-carbamic acid benzyl
ester (6c)
14-Benzyloxycarbonyl-5,7-cyclo-2,2-dimethyl-benzo[c]-1,3-
dioxolo[40,50:4,5]furo[2,3-h] 1,5-oxazonane (7d)
Thick yellow oil; yield 0.361 g (0.68 mmol, 68%); Rf ¼ 0.65 (eluent
PS–ethyl acetate 13 : 1); [a]D ꢂ26.3 (c 0.37, CHCl3); dH (300 MHz,
CDCl3) 1.26 (s, 3H), 1.48 (s, 3H), 4.33–4.64 (m, 4H), 4.84 (brs,
1H), 5.13 (s, 2H), 5.25 (d, J ¼ 10.5 Hz, 1H), 5.47 (d, J ¼ 17.1 Hz,
1H), 5.76 (m, 1H), 5.97 (d, J ¼ 6.3 Hz, 3H), 6.68 (brs, 1H), 6.98 (s,
1H), 7.26–7.32 (m, 5H); dC (75 MHz, CDCl3) 26.0, 26.7, 50.7, 67.6,
81.3, 83.7, 101.8, 105.1, 107.8, 111.0, 112.2, 112.8, 118.7, 128.5,
130.1, 131.6, 136.8, 147.5, 147.8, 156.3; IR nmax (lm): 2987,
2896, 1705, 1476, 1414, 1377, 1247, 1164, 1111, 1033, 933, 863,
757, 699 cmꢂ1; MS (EI) m/z 532, 534 (M+H+ for Br79, Br81); found:
C, 56.65; H, 4.89; N, 2.59. Calc. for C25H26BrNO7: C, 56.40; H,
4.92; N, 2.63%.
White liquid; yield 0.239 g (0.69 mmol, 69%); Rf ¼ 0.5 (eluent PS–
ethyl acetate 5 : 1); [a]D +37.6 (c 1.1, CHCl3); dH (300 MHz,
CDCl3) 1.34 (s, 3H), 1.48 (s, 3H), 2.00–2.06 (m, 1H), 2.37 (d-like,
1H), 2.49 (d, J ¼ 5.7 Hz, 1H), 4.21 (brs, 1H), 4.62 (d, J ¼ 12.9 Hz,
1H), 4.65–4.67 (m, 2H), 4.90 (d, J ¼ 12.9 Hz, 1H), 5.90 (d-like,
2H), 5.97 (d, J ¼ 3.9 Hz, 1H), 6.34 (s, 1H), 6.63 (s, 1H); dC
(75 MHz, CDCl3) 26.5, 27.3, 29.7, 33.5, 72.6, 82.9, 85.5, 101.2,
106.0, 110.3, 111.8, 116.8, 122.6, 129.4, 129.7, 132.6, 153.6; IR
nmax (lm): 2988, 2921, 2855, 1619, 1482, 1446, 1378, 1233, 1076,
1035, 935, 863, 756 cmꢂ1; HRMS: (M + Na)+ for C17H19NO6Na:
calc. 356.1110, found: 356.1116.
General procedure for compounds 7a–d and 8a–c
5,7-Cyclo-2,2-dimethyl-1,3-dioxolo[40,50:4,5]-benzo[4-
methylsulphonamido]-[40,50:4,5]furo[2,3:h] 1,5-diazonane (8a)
To a solution of each of the olens 3a–d and 6e–g (1 mmol) in
ethanol : H2O : toluene ¼ 7 : 3 : 1 (10 mL mmolꢂ1 substrate) Yellowish white liquid; yield 0.301 g (0.66 mmol, 66%); Rf ¼ 0.5
were added NaN3 (3 mmol), CuI (0.2 mmol), Na-L-ascorbate (eluent PS–ethyl acetate 5 : 1); [a]D ꢂ12.7 (c 0.22, CHCl3); dH (300
(0.1 mmol) and N,N-DMEDA (0.3 mmol) and the reaction MHz, CDCl3) 1.29 (s, 3H), 1.51 (s, 3H), 1.71–1.74 (m, 1H), 2.29–
mixture was heated under reux for 22 h under argon atmo- 2.46 (m, 5H), 4.06 (d, J ¼ 14.4 Hz, 1H), 4.47–4.52 (m, 2H), 4.87 (d,
sphere. Aer completion of the reaction (monitored by TLC), J ¼ 7.8 Hz, 1H), 5.08 (d, J ¼ 7.8 Hz, 1H), 5.69 (brs, 1H), 6.69 (d, J
the solvent from the crude mixture was evaporated and the ¼ 7.8 Hz, 1H), 6.98–7.03 (m, 1H), 7.22–7.26 (m, 3H), 7.39 (d, J ¼
residue was extracted with ethyl acetate (4 ꢁ 25) mL. The 7.2 Hz, 1H),7.60 (d, J ¼ 8.1 Hz, 2H); dC (75 MHz, CDCl3) 21.5,
organic layer was washed with NH4Cl–ammonia and water, and 26.8, 27.7, 29.7, 42.3, 48.5, 68.3, 76.9, 84.4, 105.6, 112.7, 116.1,
then dried. The solvent was evaporated under reduced pressure 122.3, 127.2, 129.4, 129.7, 130.8, 131.4, 136.3, 143.6, 152.1; IR
to give the crude product which was puried by column chro- nmax (lm): 3468, 3381, 2986, 2928, 1601, 1494, 1456, 1377, 1335,
matography over silica gel (100–200 mesh size) to furnish the 1216, 1159, 1085, 873 cmꢂ1
; HRMS: (M +
Na)+ for
pure cyclized product.
C
23H26N2O5SNa: calculated 465.1460, found: 465.1454.
4160 | RSC Adv., 2014, 4, 4155–4162
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