J.E. Aaseng et al. / Tetrahedron 66 (2010) 9790e9797
9795
128.6 (C-10), 115.4 (C-8), 114.3 (C-6), 55.6 (OCH3), 43.5 (C-1), 42.9
CH2Cl2). HPLC (Chiralcel OJ, i-PrOH/n-hexane, 10/90, 1.0 mL minꢀ1
,
(C-2), 23.9 (C-4), 20.6 (C-3). IR (thin film, NaCl): 3108 (w), 2964 (w),
1604 (m), 1558 (m), 1530 (s), 1350 (s), 1315 (s), 1265 (s), 1087 (s),
1156 (s) cmꢀ1. Anal. Calcd for C17H16N2O5S: C, 56.66; H, 4.47; N,
7.77; S, 8.90, found: C, 56.35; H, 4.30; N, 7.55; S, 8.87.
230 nm): >98% ee, tR 36.0 (S) and 59.9 (R) min. 1H NMR (300 MHz):
7.78 (app d, 2H, J 8.3 Hz, Ts H-2/H-6), 7.31 (app d, 2H, J 8.3 Hz, Ts H-
3/H-5), 7.15e7.10 (m, 3H, H-6/H-7/H-8), 6.96e6.89 (m, 1H, H-5),
4.49 (br d, 1H, J 7.7 Hz, NH), 3.68e3.54 (m, 1H, H-2), 2.95 (dd, 1H, J
16.4, 5.1 Hz, H-1), 2.87e2.69 (m, 2H, H-4), 2.59 (dd, 1H, J 16.4,
8.0 Hz, H-1), 2.45 (s, 3H, Ts CH3), 2.02e1.88 (m, 1H, H-3), 1.80e1.65
4.3.6. (1R,2S)-N-(p-Methylbenzenesulfonyl)amino-1,2,3,4-tetrahy-
dro-6-acetoxynaphthalene-1,2-imine, 2d (pTs). Data for 2d (pTs):
(m, 1H, H-3). 13C NMR (100 MHz):
d 143.3 (Ts C-1), 138.0 (Ts C-4),
White solidified foam: Rf (EtOAc/n-hexane,1:4)¼0.06. [
a
]
22 þ27.9 (c
135.1 (C-10), 133.4 (C-9), 129.7 (Ts C-3/C-5), 129.3 (C-5), 128.7 (C-8),
127.0 (Ts C-2/C-6), 126.3 (C-6), 125.9 (C-7), 49.5 (C-2), 36.4 (C-1),
29.6 (C-3), 26.9 (C-4), 21.5 (Ts CH3). IR (KBr tablet): 3243 (s), 3075
(w), 3040 (w), 2923 (m), 1735 (w), 1596 (m), 1578 (w), 1494 (m),
1451 (s), 1327 (s), 1302 (m), 1287 (m), 1236 (m), 1161 (s), 1074 (s),
946 (s), 893 (s) cmꢀ1. MS (EI) m/z (% rel int.): 302 (20), 301 (Mþ,
100), 279 (12), 130 (21), 104 (6). HRMS (EI) calcd for C17H17NO3S:
301.1136 (Mþ), found 301.1129. Data for racemic 3a:
mp¼124e125 ꢁC (from 96% EtOH).
D
1.0, CH2Cl2). HPLC (Chiralpak AD, i-PrOH/n-hexane, 10/90,
1.0 mL minꢀ1, 230 nm): 60% ee, tR 26.2 (major) and 30.3 min. 1H
NMR (400 MHz):
d 7.81 (app d, 2H, J 8.3 Hz, Ts H-2/H-6), 7.31 (app
dd, 3H, J 8.2, 2.7 Hz, H-8 and Ts H-3/H-5), 6.88 (app dd, 1H, J 8.1,
1.8 Hz, H-7), 6.80 (br s, 1H, H-5), 3.81 (d, 1H, J 7.1 Hz, H-1), 3.56 (app
d, 1H, J 7.1 Hz, H-2), 2.76 (app dt, 1H, J 14.4, 6.2 Hz, H-4), 2.52 (app
dd, 1H, J 15.6, 5.3 Hz, H-4), 2.43 (s, 3H, Ts CH3), 2.28 (s, 3H, Ac),
2.34e2.19 (m, 1H, H-3), 1.76e1.61 (m, 1H, H-3). 13C NMR (100 MHz):
d
169.5 (C]O), 150.6 (C-6), 144.4, 138.2, 135.5, 130.4, 129.6
(Ts C-3/C-5), 127.7 (Ts C-2/C-6), 126.4, 121.8 (C-5), 119.4 (C-7), 41.6
(C-1), 41.5 (C-2), 24.8 (C-4), 21.6 (Ts CH3), 21.1 (COCH3), 19.7 (C-3). IR
(KBr tablet): 3029 (m), 2938 (m), 2853 (m), 1758 (s), 1617 (m), 1597
(s), 1499 (s), 1432 (m), 1370 (s), 1208 (s), 1158 (s), 1091 (s), 1044 (m),
1015 (s), 998 (m) cmꢀ1. MS (EI) m/z (% rel int.): 357 (Mþ, 1), 188 (5),
171 (69), 162 (47), 160 (12), 155 (88), 146 (61), 147 (13), 145 (28), 13
(14), 120 (12), 108 (12), 107 (24), 91 (100), 79 (16), 77 (14), 65 (44),
63 (10), 43 (59). HRMS (EI) calcd for C19H19NO4S: 357.1035 (Mþ),
found 357.1040.
4.4.2. (S)-2-(p-Methylbenzenesulfonyl)amino-7-methoxy-1,2,3,4-tet-
rahydronaphthalene (3b). Data for 3b: White solid: Rf (Al2O3,
EtOAc/n-hexane, 1:4)¼0.23. Mp¼122e123 ꢁC (from 96% EtOH)
[a
]
23 ꢀ44.5 (c 1.01, CH2Cl2). HPLC (Chiralpak AD, i-PrOH/n-hexane,
D
10/90, 1.0 mL minꢀ1, 230 nm): 60% ee, tR 28.7 (major) and 30.3 min.
1H NMR (400 MHz):
d 7.77 (app d, 2H, J 8.3 Hz, Ts H-2/H-6), 7.31
(app d, 2H, J 8.3 Hz, Ts H-3/H-5), 6.96 (d, 1H, J 8.4 Hz, H-5), 6.69 (dd,
1H, J 8.4, 2.7 Hz, H-6), 6.47 (d, 1H, J 2.7 Hz, H-8), 4.44 (br d, 1H, J
8.1 Hz, NH), 3.74 (s, 3H, OCH3), 3.70e3.60 (m, 1H, H-2), 2.92 (dd, 1H,
J 16.2, 5.0 Hz, H-1), 2.81e2.66 (m, 2H, H-4), 2.57 (dd, 1H, J 16.2,
7.5 Hz, H-1), 2.44 (s, 3H, Ts CH3), 1.96e1.87 (m, 1H, H-3), 1.77e1.66
4.3.7. (1R,2S)-N-(p-Nitrobenzenesulfonyl)amino-1,2,3,4-tetrahydro-
6-acetoxynaphthalene-1,2-imine, 2d (pNs). Data for 2d (pNs): White
(m, 1H, H-3). 13C NMR (100 MHz):
d 157.7 (C-7), 143.4 (Ts C-4), 138.0
solid: Rf (EtOAc/n-hexane, 1:4)¼0.04. Mp¼150e156 ꢁC (from
(C-9), 134.4 (Ts C-1), 129.7 (C-5 and Ts C-2/C-6), 127.0 (C-10 and Ts
C-3/C-5), 113.8 (C-8), 112.8 (C-6), 55.2 (OCH3), 49.2 (C-2), 36.7 (C-1),
29.7 (C-3), 25.9 (C-4), 21.5 (Ts CH3). IR (KBr tablet): 3318 (br s), 3052
(w), 3009 (w), 2938 (m), 2836 (m), 1609 (s), 1505 (s), 1456 (m), 1422
(m),1322 (s),1251 (s),1161 (s),1062 8 (m), 811 (m) cmꢀ1. Anal. Calcd
for C18H21NO3S: C, 65.23; H, 6.39; N, 4.23; S, 9.67, found: C, 64.83; H,
6.35; N, 4.18; S, 9.78. Data for racemic 3b: mp¼106e107 ꢁC (from
96% EtOH).
23
EtOAc/n-hexane). [
a]
þ47.2 (c 0.69, CH2Cl2). HPLC (Chiralcel
D
OD-H, i-PrOH/n-hexane, 35/65, 1.0 mL minꢀ1, 230 nm): 35% ee, tR
21.4 and 28.6 (major) min. 1H NMR (400 MHz):
d
8.37 (app d, 2H, J
9.0 Hz, Ns), 8.13 (app d, 2H, J 9.0 Hz, Ns), 7.32 (d, 1H, J 8.2 Hz, H-8),
6.90 (app ddd,1H, J 8.2, 2.4, 0.8 Hz, H-7), 6.83 (br s,1H, H-5), 3.93 (d,
1H, J 7.1 Hz, H-1), 3.71 (app d, 1H, J 7.1 Hz, H-2), 2.73 (app dt, 1H, J
14.5, 6.5 Hz, H-4), 2.56 (app dd, 1H, J 15.8, 5.5 Hz, H-4), 2.36e2.25
(m, 1H, H-3), 2.28 (3H, s, Ac), 1.83e1.68 (m, 1H, H-3). 13C NMR
(100 MHz):
d
169.4 (C]O), 150.9 (C-6 or Ns C-4), 150.5 (C-6 or Ns C-
4.4.3. (S)-2-(p-Methylbenzenesulfonyl)amino-6-acetoxy-1,2,3,4-tet-
4), 144.5 (Ns C-1), 138.1 (C-10), 130.4 (C-8), 128.8 (Ns C-2/C-6),126.8
(C-9), 124.4 (Ns C-3/C-5), 122.0 (C-5), 119.7 (C-7), 42.6 (C-1), 42.4
(C-2), 24.6 (C-4) 21.0 (COCH3), 19.7 (C-3). IR (KBr tablet): 3110 (w),
2940 (w), 1763 (s), 1608 (m), 1525 (s), 1500 (m), 1351 (s), 1309 (s),
1207 (s), 1160 (s) cmꢀ1. HRMS (EI) calcd for C18H16N2O6S: 388.0729
(Mþ), found 388.0723.
rahydronaphthalene (3d). Data for 3d: White solid. Mp¼114e116 ꢁC
(from 96% EtOH). [
a
]
23 ꢀ30.4 (c 1.0, CH2Cl2). HPLC (Chiralpak AD, i-
D
PrOH/n-hexane, 10/90, 1.0 mL minꢀ1, 230 nm): 45% ee, tR 38.1 and
42.2 (major) min. 1H NMR (400 MHz):
d 7.76 (app d, 2H, J 8.2 Hz, Ts
H-2/H-6), 7.29 (app d, 2H, J 8.2 Hz, Ts H-3/H-5), 6.94 (app d, 1H, J
8.2 Hz, H-8), 6.81e6.76 (m, 2H, H-5/H-7), 4.68 (d, 1H, J 7.5 Hz, NH),
3.66e3.56 (m, 1H, H-2), 2.91 (dd, 1H, J 16.4, 4.6 Hz, H-1), 2.85e2.72
(m, 2H, H-4), 2.57 (dd, 1H, J 16.4, 8.0 Hz, H-1), 2.43 (s, 3H, Ts CH3),
2.26 (s, 3H, COCH3), 1.97e1.87 (m, 1H, H-3), 1.76e1.65 (m, 1H, H-3).
4.4. Aziridine ring-opening by catalytic hydrogenolysis
The ring-opening of aziridines 2a (pTs), 2b (pTs), and 2d (pTs)
were performed by adaption of a literature procedure.25 The ring
opening of 2a (Ts) is shown as a general example. Aziridine 2a (pTs)
(0.107 g, 0.358 mmol, >98% ee) was dissolved with stirring in 96%
ethanol (7 mL). Catalyst 10% Pd/C (13.1 mg) was added, the flask
was evacuated and an atmosphere of hydrogen was secured. The
mixture was stirred under balloon pressure of hydrogen for 1 h
(reaction complete according to TLC). The mixture was filtered
through a plug of silica, which was washed with ethyl acetate. The
combined filtrate and washings were evaporated to dryness to give
3a as a white solid (0.107 g, 99% yield, >98% ee according to HPLC).
Catalytic hydrogenolysis of 2b (pTs) and 2c (pTs) afforded 3b and 3d
in 95e100% yields, and without racemization.
13C NMR (100 MHz):
d 169.8 (COCH3), 148.9 (C-6), 143.5, 137.9,
136.5, 131.1, 130.3 (C-8), 129.8 (Ts C-3/C-5), 127.0 (Ts C-2/C-6), 121.5
(C-7), 119.4 (C-5), 49.4 (C-2), 36.0 (C-1), 29.3 (C-3), 27.0 (C-4), 21.6
(Ts CH3), 21.1 (COCH3). IR (CCl4): 3273 (s), 2927 (s), 2360 (s), 1959
(m), 1763 (s), 1600 (w), 1498 (m), 1438 (m), 1368 (m), 1329 (m), 1210
(s), 1162 (s), 1096 (m), 1015 (m) 909 (m) cmꢀ1. MS (EI) m/z (% rel
int.): 359 (Mþ, 4), 356 (12), 314 (11), 188 (28), 160 (18), 147 (17), 146
(100), 145 (54), 133 (17), 131 (14), 117 (18), 91 (19), 65 (11). HRMS
(EI) calcd for C19H21NO4S: 359.1191 (Mþ), found 359.1190.
4.5. Deprotecting the N-Ts group
The N-tosyl protecting groups in 3a and 3b were cleaved with
SmI2 and by initial activation of the nitrogen with a trifluoroacetyl
group in accordance with a general procedure recently described
by Moussa and Romo.26 Basic hydrolysis32 of respective N-tri-
fluoroacetyl products 12a and 12b provided target compounds 4a
4.4.1. (S)-2-(p-Methylbenzenesulfonyl)amino-1,2,3,4-tetrahydro-
naphthalene (3a). Data for 3a: White solid: Rf (EtOAc/n-hexane,
23
1:4)¼0.23. Mp¼105e106 ꢁC (from 96% EtOH). [
a
]
ꢀ64.6 (c 1.1,
D