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Z. Shen et al. / Tetrahedron 62 (2006) 9237–9246
(300 MHz, CDCl3) d 0.87 (t, J¼7.5 Hz, 3H), 1.10–1.38 (m,
4H), 1.80–1.95 (m, 2H), 2.45 (s, 3H), 4.06 (dd, J¼3.3,
8.4 Hz, 1H), 4.37 (dd, J¼8.4, 8.4 Hz, 1H), 4.45–4.48 (m,
1H), 7.35 (d, J¼8.1 Hz, 2H), 7.96 (d, J¼8.1 Hz, 2H); 13C
NMR (75 MHz, CDCl3) d 13.7, 21.6, 22.2, 25.4, 33.2,
57.2, 67.5, 128.2, 129.6, 135.0, 145.4, 152.2; IR (KBr): n
2962, 2927, 2854, 1778, 1596, 1486, 1395, 1363, 1174,
1148, 1091, 820, 667, 608, 547 cmꢀ1; ESIMS m/z: 298
(M+H+), 315 (M+NH4+). Anal. Calcd for C14H19NO4S: C,
56.55; H, 6.44; N, 4.71. Found: C, 56.30; H, 6.37; N,
4.99; HPLC analysis: 99% ee (DAICEL CHIRALCEL OJ,
4.3.7. (D)-N-Tosyl-4-methyl-1,3-oxazolidin-2-one (7f).
White solid (yield: 97%), mp 94–97 ꢁC. 1H NMR
(300 MHz, CDCl3) d 1.53 (d, J¼6.3 Hz, 3H), 2.45 (s, 3H),
3.93 (dd, J¼8.4, 3.6 Hz, 1H), 4.43 (dd, J¼8.4, 8.4 Hz,
1H), 4.53–4.60 (m, 1H), 7.36 (d, J¼8.4 Hz, 2H), 7.94 (d,
J¼8.4 Hz, 2H); 13C NMR (75 MHz, CDCl3) d 20.5, 21.6,
53.5, 69.5, 128.3, 129.7, 135.0, 145.5, 152.0; IR (KBr): n
1783, 1596, 1363, 1170, 664, 546 cmꢀ1; ESIMS m/z: 256
(M+H+), 273 (M+NH4+). Anal. Calcd for C11H13NO4S: C,
51.75; H, 5.13; N, 5.49. Found: C, 51.96; H, 5.19; N, 5.33;
HPLC analysis: 39% ee (DAICEL CHIRALPAK AD-H,
eluent, hexane/2-propanol¼70/30, flow rate 0.7 mL minꢀ1
,
eluent, hexane/2-propanol¼90/10, flow rate 0.8 mL minꢀ1
,
detection 230 nm light), tR of minor-isomer 18.13 min and
detection 230 nm light), tR of minor-isomer 19.13 min
and that of major-isomer 26.79 min; [a]2D0 +54.9 (c 1.03,
CHCl3).
that of major-isomer 23.21 min; [a]2D0 +14.7 (c 1.04, CHCl3).
4.3.8. (L)-N-Acetyl-4,5,5-trimethyl-1,3-oxazolidin-2-one
(7g). White solid (yield: 96%), mp 39–40 ꢁC (lit.10a mp
4.3.4. (L)-N-Tosyl-4-ethyl-1,3-oxazolidin-2-one (7c).
White solid (yield: 97%), mp 87–89 ꢁC. 1H NMR
(300 MHz, CDCl3) d 0.88 (t, J¼7.2 Hz, 3H), 1.82–2.01 (m,
2H), 2.45 (s, 3H), 4.08 (dd, J¼3.3, 8.7 Hz, 1H), 4.38 (dd,
J¼8.7, 8.7 Hz, 1H), 4.43–4.50 (m, 1H), 7.35 (d, J¼8.4 Hz,
2H), 7.96 (d, J¼8.4 Hz, 2H); 13C NMR (75 MHz, CDCl3)
d 7.5, 21.6, 26.4, 57.9, 67.0, 128.3, 129.7, 135.0, 145.5,
152.3; IR (KBr): n 1766, 1597, 1373, 1175, 1111, 815, 664,
545 cmꢀ1; ESIMS m/z: 270 (M+H+), 287 (M+NH+4). Anal.
Calcd for C12H15NO4S: C, 53.52; H, 5.61; N, 5.20. Found:
C, 53.72; H, 5.60; N, 5.15; HPLC analysis: 27% ee (DAICEL
CHIRALPAK AD-H, eluent, hexane/2-propanol¼90/10,
flow rate 0.8 mL minꢀ1, detection 230 nm light), tR of
major-isomer 21.71 min and that of minor-isomer
32.54 min; [a]2D0 ꢀ10.7 (c 1.01, CHCl3).
1
42 ꢁC). H NMR (300 MHz, CDCl3) d 1.28 (d, J¼6.5 Hz,
3H), 1.41 (s, 3H), 1.43 (s, 3H), 2.52 (s, 3H), 4.17 (q,
J¼6.5 Hz, 1H); IR (KBr): n 1762, 1702 cmꢀ1; ESIMS m/z:
171, 127, 114, 101, 84, 70, 59, 43, 39; HPLC analysis:
80% ee (DAICEL CHIRALCEL OJ-H, eluent, hexane/
2-propanol¼90/10, flow rate 0.8 mL minꢀ1, detection
200 nm light), tR of major-isomer 9.04 min and that of
minor-isomer 10.13 min; [a]2D0 ꢀ51.4 (c 0.54, EtOH).
4.4. Synthesis of L-lysine
4.4.1. (S)-N-Tosyl-4-((40-dibenzylamino)butyl)-1,3-oxa-
zolidin-2-one (11). To a solution of THF (31 mL) and 2 N
HCl (7.6 mL) was added (S)-2 (2.52 g, 6.6 mmol) at room
temperature and the mixture was stirred for 30 min at room
temperature. After triethylamine (2.4 mL, 17.2 mmol) was
introduced via a syringe and stirred for 5 min at 0 ꢁC, dibenz-
ylamine (1.3 mL, 6.6 mmol) was added to the mixture and
the reaction mixture was stirred for 10 min at 0 ꢁC. Then, so-
dium cyanoborohydride (411.3 mg, 6.6 mmol) was added in
one portion at 0 ꢁC. The reactionmixturewas stirred for 8 h at
room temperature and then poured into 2 N HCl (pH¼2) at
0 ꢁC. Concentrated NaOH solution was added to the mixture
at 0 ꢁC to make the solution basic (pH¼12). Then, saturated
NaCl solution (30 mL) was added and the reaction mixture
was extracted with ethyl acetate (3ꢂ30 mL). The combined
organic extracts were washed with brine (30 mL), dried
(Na2SO4), filtered, and concentrated. The residue was puri-
fied by column chromatography on silica gel (petroleum
ether/ethyl acetate/Et3N¼80/10/1 to 100/20/1 (v/v/v)) to
4.3.5. (L)-N-Tosyl-4,5,5-trimethyl-1,3-oxazolidin-2-one
1
(7d). White solid (yield: 96%), mp 99–102 ꢁC. H NMR
(300 MHz, CDCl3) d 1.35 (d, J¼4.8 Hz, 3H), 1.40 (s, 3H),
1.42 (s, 3H), 2.45 (s, 3H), 4.14 (q, J¼4.8 Hz, 1H), 7.35
(d, J¼8.4 Hz, 2H), 7.95 (d, J¼8.4 Hz, 2H); 13C NMR
(75 MHz, CDCl3) d 16.4, 21.4, 21.6, 27.4, 62.2, 82.3,
128.1, 129.6, 135.1, 145.3, 151.1; IR (KBr): n 1774, 1596,
1359, 1330, 1278, 1171, 1160, 1131, 1089, 818, 728, 663,
581, 549 cmꢀ1; ESIMS m/z: 284 (M+H+), 301 (M+NH+4).
Anal. Calcd for C13H17NO4S: C, 55.11; H, 6.05; N, 4.94.
Found: C, 55.28; H, 6.05; N, 4.90; HPLC analysis: 87% ee
(DAICEL CHIRALPAK AD-H, eluent, hexane/2-prop-
anol¼90/10, flow rate 0.8 mL minꢀ1, detection 230 nm
light), tR of minor-isomer 12.04 min and that of major-isomer
13.38 min; [a]2D0 ꢀ25.7 (c 1.11, CHCl3).
1
give white solid (S)-11 in 56% yield, mp 88–90 ꢁC. H
4.3.6. (L)-N-Tosyl-4-methyl-1-oxa-3-aza-spiro[4,5]-
decan-2-one (7e). White solid (yield: 100%), mp 85–
NMR (300 MHz, CDCl3) d 1.20–1.30 (m, 2H), 1.42–1.50
(m, 2H), 1.63–1.79 (m, 2H), 2.35 (t, J¼6.9 Hz, 2H), 2.41
(s, 3H), 3.48 (d, J¼13.5 Hz, 2H), 3.53 (d, J¼13.5 Hz, 2H),
3.95 (dd, J¼8.4, 3.3 Hz, 1H), 4.31 (dd, J¼8.4, 8.4 Hz, 1H),
4.38–4.41 (m, 1H), 7.21–7.34 (m, 12H), 7.90 (d, J¼8.4 Hz,
2H); 13C NMR (75 MHz, CDCl3) d 20.8, 21.5, 26.5, 33.0,
52.6, 57.0, 58.2, 67.3, 126.7, 128.08, 128.13, 128.6, 129.6,
134.9, 139.6, 145.3, 152.1; IR (KBr): n 2943, 2799, 1786,
1598, 1494, 1390, 1174, 1091, 911, 666 cmꢀ1; EIMS m/z:
492 (M+), 210, 181, 155, 91, 65, 43. Anal. Calcd for
C28H32N2O4S: C, 68.27; H, 6.55; N, 5.69. Found: C, 68.01;
H, 6.53; N, 5.58; [a]2D0 +38.4 (c 1.01, CHCl3).
1
87 ꢁC. H NMR (300 MHz, CDCl3) d 1.37 (d, J¼6.6 Hz,
3H), 1.26–1.82 (m, 10H), 2.45 (s, 3H), 4.14 (q, J¼6.6 Hz,
1H), 7.34 (d, J¼8.4 Hz, 2H), 7.95 (d, J¼8.4 Hz, 2H); 13C
NMR (75 MHz, CDCl3) d 15.7, 21.6, 21.8, 22.0, 24.7,
30.4, 36.1, 61.6, 83.5, 128.2, 129.7, 135.3, 145.2, 151.1;
IR (KBr): n 1768, 1598, 1370, 1359, 1174, 1124, 1029,
603, 548 cmꢀ1; ESIMS m/z: 324 (M+H+), 341 (M+NH+4).
Anal. Calcd for C16H21NO4S: C, 59.42; H, 6.52; N, 4.33.
Found: C, 59.67; H, 6.74; N, 4.13; HPLC analysis: 81% ee
(DAICEL CHIRALCEL OJ-H, eluent, hexane/2-prop-
anol¼90/10, flow rate 0.8 mL minꢀ1, detection 230 nm
light), tR of major-isomer 18.71 min and that of minor-
isomer 23.04 min; [a]2D0 ꢀ27.4 (c 1.0, CHCl3).
4.4.2. (2S)-6-Dibenzylamino-2-tosylaminohexanol (12).
To a solution of (S)-11 (1.7 g, 3.5 mmol) in THF (48 mL)