9
To a solution of the corresponding β-nitroamine derivative 3 (0.50 mmol) in EtOH (4.0 mL) was added
commercially available Raney nickel (1.0 g, 0.4 mL, 50% slurry in water) and the mixture was vigorously
stirred at room temperature under a hydrogen atmosphere (1 atm) for 40 h. The resulting suspension was
filtered through a short pad of Celite with EtOH (40 mL) and concentrated in vacuo (15 Torr). The residue was
purified by column chromatography (silica gel, EtOAc/MeOH) to yield pure compounds 4. Yields are given in
Table 1. Physical, spectroscopic, and analytical data follow.
4.3.1. (5R,1’R,RS)-5-[1-(tert-Butanesulfinylamino)-2-methylpropyl]pyrrolidin-2-one (4aa).- White solid; mp
20
150–152 ºC (hexane/CH2Cl2); [α]D +1.5 (c = 0.46, CH2Cl2); Rf 0.31 (EtOAc/EtOH: 9/1); IR ν (film) 3394,
3224, 3062, 2977, 1697, 1538, 1423, 1164, 1029, 917, 779, 682 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.31 (br s,
1H), 3.68–3.62 (m, 1H), 3,33 (d, J = 10.0 Hz, 1H), 2.88 (ddd, J = 9.9, 8.5, 2.8 Hz, 1H), 2.37 (dd, J = 10.1, 5.8
Hz, 2H), 2.18–2.14 (m, 1H), 1.95–1.88 (m, 1H), 1.80–1.75 (m, 1H), 1.27 (s, 9H), 0.96 (d, J = 6.7 Hz, 3H), 0.86
13
(d, J = 6.8 Hz, 3H); C NMR (100 MHz, CDCl3) δ 177.1 (C), 68.3, 57.8 (CH), 56.8 (C), 31.2 (CH2), 29.1
(CH), 25.7 (CH2), 23.0, 20.8, 15.6 (CH3); LRMS (EI) m/z 203 (M+−C4H9, 6%), 192 (12), 167 (13), 113 (20),
111 (21), 99 (18), 85 (28), 84 (99), 83 (21), 72 (89), 57.2 (100), 56 (20), 55 (28), 43 (31), 41 (50); HRMS (ESI-
TOF) Calcd for C8H15N2O2S [M+–C4H9] 203.0854, found 203.853.
4.3.2. (5S,1’R,RS)-5-[1-(tert-Butanesulfinylamino)-2-methylpropyl]pyrrolidin-2-one (4ab).- White solid; mp
20
142–144 ºC (hexane/CH2Cl2); [α]D –3.4 (c = 0.49, CH2Cl2); Rf 0.26 (EtOAc/EtOH: 9/1); IR ν (film) 3166,
2969, 2923, 1677, 1535, 1465, 1149, 1025, 790, 678 cm-1; 1H NMR (400 MHz, CDCl3) δ 6.98 (br s, 1H), 3.85–
3.80 (m, 1H), 3,57 (d, J = 7.6 Hz, 1H), 3.16–3.12 (m, 1H), 2.40–2.23 (m, 3H), 2.14–2.10 (m, 1H), 1.93–1.88
(m, 1H), 1.27 (s, 9H), 0.98 (d, J = 6.8 Hz, 3H), 0.93 (d, J = 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 178.5
(C), 64.5 (CH), 56.8 (C), 57.8 (CH), 56.6 (CH), 30.1 (CH2), 29.7 (CH), 24.0 (CH2), 23.0, 20.5, 16.9 (CH3);
LRMS (EI) m/z 203 (M+−C4H9, 8%), 167 (13), 149 (30), 135 (31), 111 (18), 99 (16), 85 (35), 84 (88), 72 (80),
57 (100), 56 (23), 55 (47), 43 (60), 41 (51); HRMS (ESI-TOF) Calcd for C8H14NO [M+–C4H9NOS-CH3]
140.1075, found 140.1068.
4.3.3. (5R,1’R,RS)-5-[1-(tert-Butanesulfinylamino)-3-methylbutyl]pyrrolidin-2-one (4ba).- White solid; mp
20
115–117 ºC (hexane/CH2Cl2); [α]D –24.8 (c = 0.46, CH2Cl2); Rf 0.63 (EtOAc/EtOH: 9/1); IR ν (film) 3297,
3220, 2954, 2877, 1697, 1666, 1415, 1168, 1041, 983, 914, 887, 829 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.37
(br s, 1H), 3.50 (q, J = 7.7 Hz, 1H), 3,31 (d, J = 10.3 Hz, 1H), 3.13–2.95 (m, 2H), 2.40–2.32 (m, 2H), 2.23–2.10
13
(m, 2H), 1.87–1.65 (m, 2H), 1.24 (s, 9H), 0.93 (d, J = 6.7 Hz, 3H), 0.86 (d, J = 6.6 Hz, 3H); C NMR (100
MHz, CDCl3) δ 177.5 (C), 62.3, 60.2 (CH), 56.8 (C), 41.6, 31.1, 25.6 (CH2), 24.1 (CH), 23.8, 22.9, 20.9 (CH3);
LRMS (EI) m/z 218 (M+−C4H8, 26%), 218 (27), 134 (28), 112 (13), 86 (16), 84 (100), 57 (23), 43 (15), 41 (17);
HRMS (ESI-TOF) Calcd for C5H9N2O [M+–C4H9NOS–C4H8] 113.0715, found 113.0710.
4.3.4. (5S,1’R,RS)-5-[1-(tert-Butanesulfinylamino)-3-methylbutyl]pyrrolidin-2-one (4bb).- White solid; mp 35–
20
37 ºC (hexane/CH2Cl2); [α]D +6.3 (c = 0.55, CH2Cl2); Rf 0.57 (EtOAc/EtOH: 9/1); IR ν (film) 3409, 3208,
2954, 2869, 1681, 1458, 1365, 1268, 1168, 1041, 914, 883 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.47 (br s, 1H),
4.29 (d, J = 9.1 Hz, 1H), 4.20−4.05 (m, 1H), 3.39–3.18 (m, 1H), 2.42–2.27 (m, 2H), 2.26–2.08 (m, 1H), 1.88–
13
1.67 (m, 2H), 1.47−1.31 (m, 2H), 1.23 (s, 9H), 0.92 (d, J = 6.6 Hz, 3H), 0.88 (d, J = 6.6 Hz, 3H); C NMR
(100 MHz, CDCl3) δ 178.9 (C), 59.4, 59.0 (CH), 56.8 (C), 38.5, 30.4, 24.4 (CH2), 23.8 (CH), 23.0, 22.9, 21.4
(CH3); LRMS (EI) m/z 218 (M+−C4H8, 33%), 218 (33), 134 (36), 112 (18), 86 (17), 85 (10), 84 (100), 57 (26),
43 (13), 41 (20); HRMS (ESI-TOF) Calcd for C5H9N2O [M+–C4H9NOS–C4H8] 113.0715, found 113.0716.
4.3.5. (5R*,1’R,RS)-5-[1-(tert-Butanesulfinylamino)nonyl]pyrrolidin-2-one (4c).- Mixture of diastereoisomers
(1:1); yellow oil; Rf 0.31 (hexane/EtOAc: 1/1); IR ν (film) 3220, 2923, 2858, 1681, 1454, 1261, 1033, 929 cm-1;
1H NMR (300 MHz, CDCl3) δ 7.73 (br s, 1H), 7.49 (2 br s, 1H), 4.37 (d, J = 8.5, Hz, 1H), 4.06–4.01 (m, 1H),
3.87 (d, J = 9.6 Hz, 1H), 3.56 (q, J = 7.4 Hz, 1H), 3.19–3.13 (m, 1H), 2.99–2.92 (m, 1H), 2.34–2.24 (m, 4H),
2.18–2.09 (m, 2H), 1.82–1.72 (m, 2H), 1.49–1.21 (m, 26H), 1.20 (s, 9H), 1.18 (s, 9H), 0.83 (t, J = 6.9 Hz, 6H);
13C NMR (75 MHz, CDCl3) δ 178.7, 177.8 (C), 63.4, 60.6, 59.3, 59.1 (CH), 56.6, 56.5 (C), 32.4, 31.8, 31.0,
30.3, 29.6, 29.4, 29.3, 29.1, 26.0, 25.6, 25.0 (CH2), 22.8 (CH3), 22.7, 22.6 (CH2), 14.0 (CH3); LRMS (EI) m/z