Organic & Biomolecular Chemistry
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(10/1) to give pure trans-12a as a white solid (3.5 mg, 16%). HPLC
trans-12b: [α]2D5 = −56.5 (c, 0.5, CHCl3); IR (film): 2970, 2926,
(Chiralcel AD-H column, 214 nm, hexane–2-propanol = 98/2, flow 2881, 1785, 1706, 1456, 1386, 1351, 1259, 1211, 1107, 1012,
rate = 0.7 mL min−1), tR = 20.852, 22.688, 24.952, 25.352 min.
926, 761, 703 cm−1 1H NMR (400 MHz, CDCl3): δ (ppm)
;
trans-13a: [α]2D5 = 97.8 (c, 1.0, CHCl3); IR (film): 2969, 2939, 7.24–7.36 (m, 5H), 5.88 (dd, J = 10.8, 17.6 Hz, 1H), 5.35 (dd, J =
2878, 1781, 1695, 1507, 1464, 1386, 1354, 1302, 1205, 1153, 0.8, 17.2 Hz, 1H), 5.22 (dd, J = 0.8, 11.2 Hz, 1H), 4.67–4.72 (m,
1
1057, 1014, 990, 923, 773, 754, 725 cm−1; H NMR (300 MHz, 1H), 4.24–4.28 (m, 1H), 4.21 (dd, J = 2.0, 9.2 Hz, 1H), 3.36 (dd,
CDCl3): δ (ppm) 5.86 (dd, J = 10.8, 17.1 Hz, 1H), 5.33 (d, J = J = 3.2, 13.2 Hz, 1H), 3.05 (d, J = 13.2 Hz, 1H), 2.81 (dd, J =
17.1 Hz, 1H), 5.22 (d, J = 10.8 Hz, 1H), 4.56–4.61 (m, 1H), 10.0, 13.2 Hz, 1H), 2.72 (d, J = 13.2 Hz, 1H), 2.11–2.17 (m, 2H),
4.31–4.37 (t, J = 8.7 Hz, 1H), 4.16–4.26 (m, 1H), 2.81 (s, 2H), 1.61–1.69 (m, 2H), 0.92 (t, J = 7.6 Hz, 3H), 0.88 (t, J = 7.6 Hz,
2.37–2.44 (m, 1H), 2.24–2.34 (m, 1H), 2.08–2.18 (m, 1H), 3H); 13C NMR (100 MHz, CDCl3): δ (ppm) 172.2, 152.1, 140.5,
1.58–1.66 (m, 2H), 0.83–0.94 (m, 12H); 13C NMR (100 MHz, 135.2, 129.5, 129.0, 127.4, 114.5, 91.8, 88.5, 66.5, 57.0, 51.0,
CDCl3): δ (ppm) 172.5, 153.0, 140.7, 114.9, 91.8, 88.6, 63.7, 37.9, 29.9, 26.2, 8.8; MS (ESI): m/z (relative intensity): 360.1
59.7, 52.0, 30.2, 28.1, 26.8, 18.3, 14.6, 8.9, 8.8; MS (ESI): m/z [M + H]+; HRMS (ESI): Calculated for C20H29N2O5 [M + NH4]+:
(relative intensity): 312 [M + H]+; HRMS (ESI): Calculated for 377.2071, found: 377.2066.
C16H25NO5Na [M + Na]+: 334.1628, found: 334.1625; Anal. Cal-
culated for C16H25NO5: C, 61.72; H, 8.09; N, 4.50, found: C, phenyloxazolidin-2-one (trans-12c), (S)-3-((3S,5S)-3,5-diethyl-5-
(S)-3-((3R,5R)-3,5-Diethyl-5-vinyl-1,2-dioxolane-3-carbonyl)-4-
62.03; H, 8.12; N, 4.48.
vinyl-1,2-dioxolane-3-carbonyl)-4-phenyl
oxazolidin-2-one
trans-12a: M.p.: 61–62 °C; [α]2D5 = −23.4 (c, 0.5, CHCl3); (trans-13c) and (S)-3-((3R,5S)-3,5-diethyl-5-vinyl-1,2-dioxolane-
IR (film): 2968, 2939, 2880, 1782, 1709, 1488, 1464, 1387, 1364, 3-carbonyl)-4-phenyloxazolidin-2-one (cis-14c). Prepared from
1301, 1257, 1205, 1145, 1058, 990, 927, 774, 722 cm−1 1H 76 mg of a 1 : 1 mixture of trans-10c and trans-11c using the
;
NMR (300 MHz, CDCl3): δ (ppm) 5.86 (dd, J = 10.8, 17.1 Hz, general procedure. The 1,2-dioxolane product was carefully
1H), 5.31 (d, J = 17.1 Hz, 1H), 5.20 (d, J = 6.9 Hz, 1H), 4.48–5.23 purified by flash chromatography (hexanes–EtOAc, 20/1→3/1)
(m, 1H), 4.33–4.38 (t, J = 8.7 Hz, 1H), 4.39–2.47 (m, 1H), 3.02 to give trans-12c, trans-13c and cis-14c (colorless oil, 84 mg) in
(d, J = 13.2 Hz, 1H), 2.76 (d, J = 13.2 Hz, 1H), 2.39–2.47 (m, a total 100% yield. HPLC (Chiralcel IC column, 214 nm,
1H), 2.10–2.18 (m, 2H), 1.58–1.68 (m, 2H), 0.83–0.94 (m, 12H); hexane–2-propanol = 80/20, flow rate = 0.7 mL min−1), tR
13C NMR (100 MHz, CDCl3): δ (ppm) 172.3, 153.1, 140.8, 114.7, 23.72, 37.85, 44.72 min.
=
92.2, 88.6, 64.0, 60.3, 51.5, 30.2, 28.9, 26.5, 18.3, 15.1, 9.0, 8.9;
trans-12c, trans-13c and cis-14c: IR (film): 3032, 2975, 2938,
MS (ESI): m/z (relative intensity): 312 [M + H]+; HRMS (EI): Cal- 2881, 1785, 1709, 1444, 1382, 1316, 1256, 1199, 1111, 1043,
culated for C16H25NO5 [M]+: 311.1733, found: 311.1729.
980, 905, 757, 705 cm−1; H NMR (300 MHz, CDCl3): δ (ppm)
1
(S)-4-Benzyl-3-((3R,5R)-3,5-diethyl-5-vinyl-1,2-dioxolane-3-car- 7.32–7.41 (m, 5H), 5.38 (dd, J = 10.8, 17.4 Hz, 1H), 5.52–5.57
bonyl)oxazolidin-2-one (trans-12b), (S)-4-benzyl-3-((3S,5S)-3,5- (m, 1H), 5.30 (d, J = 17.4 Hz, 1H), 5.22 (d, J = 11.4 Hz, 1H),
diethyl-5-vinyl-1,2-dioxolane-3-carbonyl)oxazolidin-2-one (trans- 4.70–4.80 (m, 1H), 4.29–4.34 (m, 1H), 2.89–3.08 (m, 1H), 2.69
13b) and (S)-4-benzyl-3-((3R,5S)-3,5-diethyl-5-vinyl-1,2-dioxolane- (d, J = 13.2 Hz, 1H), 2.05–2.18 (m, 2H), 1.38–1.45 (m, 2H),
3-carbonyl)oxazolidin-2-one (cis-14b). Prepared from 145 mg of 0.67–0.88 (m, 6H); 13C NMR (100 MHz, CDCl3): δ (ppm) 173.5,
a 1 : 1 mixture of trans-10b and trans-11b using the general pro- 152.5, 140.3, 138.1, 129.2 (129.0), 129.0 (128.8), 126.6 (125.9),
cedure. The 1,2-dioxolane product was carefully purified by 114.5, 91.8, 88.3 (88.3), 70.2, 59.2, 52.2, 29.8, 26.1, 8.8, 8.3; MS
flash chromatography (hexanes–EtOAc, 20/1→5/1) to give trans- (ESI): m/z (relative intensity): 346.2 [M + H]+; HRMS (ESI): Cal-
12b, trans-13b and cis-14b (160 mg, pale yellow oil) as a culated for C19H23NO5Na [M
+
Na]+: 368.1468, found:
mixture in a total 100% yield. The mixture was then separated 368.1474; Anal. Calculated for C19H23NO5: C, 66.07; H, 6.71; N,
by preparative HPLC to give trans-13b (pale yellow oil, 80 mg) 4.06, found: C, 65.89; H, 6.76; N, 3.97.
and trans-12b (pale yellow oil, 50 mg). HPLC (Chiralcel OD-H
column, 214 nm, hexane–2-propanol = 80/20, flow rate = (4-nitrobenzyl)oxazolidin-2-one (trans-12d), (S)-3-((3S,5S)-3,5-
0.7 mL min−1), tR = 20.55, 26.41, 29.78 min.
diethyl-5-vinyl-1,2-dioxolane-3-carbonyl)-4-(4-nitrobenzyl)oxazo-
trans-13b: [α]2D5 = 119.1 (c, 1.0, CHCl3); IR (film): 2971, 2938, lidin-2-one (trans-13d) and (S)-3-((3R,5S)-3,5-diethyl-5-vinyl-1,2-
2881, 1785, 1706, 1456, 1378, 1351, 1257, 1212, 1110, 1076, dioxolane-3-carbonyl)-4-(4-nitrobenzyl)oxazolidin-2-one (cis-
(S)-3-((3R,5R)-3,5-Diethyl-5-vinyl-1,2-dioxolane-3-carbonyl)-4-
1
1015, 925, 762, 703 cm−1; H NMR (400 MHz, CDCl3): δ (ppm) 14d). Prepared from 67 mg of a 1 : 1 mixture of trans-10d and
7.22–7.34 (m, 5H), 5.86 (dd, J = 11.2, 17.6 Hz, 1H), 5.33 (d, J = trans-11d using the general procedure. The 1,2-dioxolane
17.6 Hz, 1H), 5.22 (d, J = 10.8 Hz, 1H), 4.76–4.79 (m, 1H), product was carefully purified by flash chromatography
4.18–4.23 (m, 2H), 3.56 (dd, J = 2.0, 13.2 Hz, 1H), 2.81 (s, 2H), (hexanes–EtOAc, 10/1→1/1) to give trans-12d, trans-13d and cis-
2.68 (dd, J = 10.4, 13.2 Hz, 1H), 2.26–2.32 (m, 1H), 2.06–2.13 14d (pale yellow solid, 73 mg) in a total 100% yield. HPLC
(m, 1H), 1.59–1.65 (m, 2H), 0.91 (t, J = 7.6 Hz, 3H), 0.85 (t, J = (Chiralcel IC column, 214 nm, hexane–2-propanol = 0/50, flow
7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ (ppm) 172.2, 152.3, rate = 0.5 mL min−1), tR = 24.31, 31.56 min.
140.4, 135.2, 129.4, 129.0, 127.4, 114.7, 91.5, 88.5, 66.7, 56.5,
trans-12d, trans-13d and cis-14d: M.p.: 104 °C; IR (film):
51.5, 37.8, 29.9, 26.5, 8.7; MS (ESI): m/z (relative intensity): 3083, 2974, 2938, 2881, 1789, 1703, 1645, 1605, 1518, 1482,
360.2 [M + H]+; HRMS (ESI): Calculated for C20H26NO5 1462, 1387, 1349, 1317, 1257, 1211, 1110, 923, 860, 832,
[M + H]+: 360.1805, found: 360.1801.
765 cm−1; 1H NMR (300 MHz, CDCl3): δ (ppm) 8.21–8.23 (d, J =
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Org. Biomol. Chem., 2014, 12, 3686–3700 | 3693