N. A. Shaye et al. / Tetrahedron: Asymmetry 22 (2011) 439–463
455
dC (100 MHz; CDCl3) 174.7 (NC@O), 157.6 (i-CO; Ar), 152.9 (OC@O;
Ar), 135.3, 135.4, 133.8 and 129.8 (4 ꢃ i-C; Ar and Ph), 129.3, 127.1,
126.7, 126.6, 118.9 and 105.5 (6 ꢃ CH; Ar), 128.9,2 128.82 and
127.31 (5 ꢃ CH; Ph), 65.8 (CH2O), 55.8 (BnNCH), 55.2 (CH3O),
42.9 (ArCHCH3), 37.9 (CH2Ph) and 19.4 (ArCHCH3) (Found
(i-PrCHN), 55.3 (OCH3), 43.2 (ArCHCH3), 27.9 (CH(CH3)2), 18.7
(CH3ACHCH3B), 17.7 (CHA3 CHCH3B) and 14.0 (ArCHCH3) (Found MH+,
342.1701; C20H24NO4 requires MH+, 342.1700).
4.43. Synthesis of 4-phenyl-3-[2-(6-methoxynaphthalene-2-yl)-
propanoyl]-oxazolidin-2-one (rac)-anti-9 and 4-phenyl-3-[2-(6-
methoxynaphthalene-2-yl)-propanoyl]-oxazolidin-2-one (rac)-
syn-9
þ
MNH4þ, 407.1960; C24H27N2O4 requires MNH4 407.1965); and
the oxazolidin-2-one (rac)-syn-33 (0.274 g, 52%) as a white crystal-
line solid; RF [light petroleum ether (bp 40–60 °C)/diethyl ether
(1:1)] 0.35; mp 134–136 °C; mmax (CHCl3) cmꢀ1 1778 (OC@O) and
1699 (NC@O); dH (400 MHz; CDCl3) 7.82 (1H, d, J 1.5, CH; Ar),
7.73 (2H, d, J 8.6, 2 ꢃ CH; Ar), 7.54 (1H, dd, J 8.6 and 1.5; Ar),
7.15–7.10 (3H, m, 3 ꢃ CH; Ph), 7.13 (1H, br s, CH; Ar), 7.05–7.02
(1H, br d, J 8.6, CH; Ar), 6.88 (2H, br d, J 7.1, 2 ꢃ CH; Ph), 5.26
(1H, q, J 6.9, ArCHCH3), 4.79–4.71 (1H, m, BnCHN), 4.16 (1H, t, J
8.9, CHAHBO), 4.04 (1H, dd, J 8.9 and 3.1, CHAHBO), 3.91 (3H, s,
OCH3), 3.06 (1H, dd, J 13.6 and 3.5, CHAHBPh), 2.55 (1H, dd, J 13.6
and 8.7, CHAHBPh) and 1.60 (3H, d, J 6.9, ArCHCH3); dC (100 MHz;
CDCl3) 174.5 (NC@O), 157.7 (i-CO; Ar), 152.9 (OC@O), 135.2,
134.8, 133.7 and 129.7 (4 ꢃ i-C; Ar and Ph), 129.3, 127.2, 126.6,
125.9, 118.9 and 105.5 (6 ꢃ CH; Ar), 128.9,2 128.72 and 128.51
In the same way as the oxazolidin-2-one (rac)-20, n-BuLi
(0.6 mL, 2.5 M in hexane, 1.50 mmol), 4-phenyl-oxazolidin-2-one
(rac)-8 (0.22 g, 1.36 mmol) and the pentafluorophenyl 2-(6-
methoxynaphthalene-2-yl)propanoate (rac)-6 (0.59 g, 1.50 mmol),
gave a separable mixture of two diastereoisomeric oxazolidin-2-
ones 9 (ratio: 95:5 syn-:anti-). The crude residue was purified by
flash column chromatography on silica gel eluting with [light
petroleum ether (bp 40–60 °C)/diethyl ether (7:3)] to give oxazoli-
din-2-one (rac)-anti-9 (16 mg, 3%) as a colourless oil; RF [light
petroleum ether (bp 40–60 °C)/diethyl ether (1:1)] 0.45; mmax
(CHCl3) cmꢀ1 1782 (OC@O) and 1705 (NC@O); dH (400 MHz;
CDCl3) 7.75 (1H, s, CH; Ar), 7.69 (2H, dd, J 8.6 and 2.6, 2 ꢃ CH;
Ar), 7.49–7.30 (6H, m, 6 ꢃ CH; Ar and Ph), 7.15–7.10 (2H, m,
2 ꢃ CH; Ar and Ph), 5.31 (1H, dd, J 8.6 and 3.3, CHAHBO), 5.27
(1H, q, J 7.0, ArCHCH3), 4.47 (1H, t, J 8.6, CHAHBO), 4.17 (1H, dd, J
8.6 and 3.2, CHAHBO), 3.90 (3H, s, CH3O) and 1.48 (3H, d, J 7.0,
ArCHCH3); dC (100.6 MHz; CDCl3) 174.1 (NC@O), 157.6 (i-OC; Ar),
153.2 (OC@O), 139.3, 135.3, 133.7 and 128.8 (4 ꢃ i-C; Ar), 129.2,
127.1, 126.8, 126.7, 118.9 and 105.5 (6 ꢃ CH; Ar), 128.8,2 128.61
and 125.72 (5 ꢃ CH; Ph), 69.6 (CH2O), 58.0 (PhCHN), 55.2 (CH3O),
43.0 (ArCHCH3) and 19.3 (ArCHCH3) (Found MH+, 376.1545;
(5 ꢃ CH; Ph), 65.8 (CH2O), 55.2 (CH3O), 54.8 (BnCHN), 43.0
þ
(ArCHCH3), 37.3 (CH2Ph) and 19.0 (ArCHCH3) (Found MNH4
,
407.1971. C24H27ClN2O4 requires MNH4þ, 407.1965).
4.42. Synthesis of 4-isopropyl-3-[2-(6-methoxy-naphthlene-2-
yl)propanoyl]-oxazolidin-2-one (rac)-anti-40 and 4-isopropyl-
3-[2-(6-methoxy-naphthlene-2-yl)propanoyl]-oxazolidin-
2-one (rac)-syn-40
In the same way as the oxazolidin-2-one (rac)-20, n-BuLi
(0.6 mL, 2.5 M in hexane, 1.50 mmol), oxazolidin-2-one (rac)-13
(0.17 g, 1.36 mmol) and the pentafluorophenyl 2-(6-methoxy-
naphthalene-2-yl)propanoate (rac)-6 (0.59 g, 1.50 mmol), gave a
separable mixture of two diastereoisomeric oxazolidin-2-ones 40
(ratio: 92:8 syn-:anti-). The crude residue was purified by flash col-
umn chromatography on silica gel eluting with light petroleum
ether (bp 40–60 °C)/diethyl ether (7:3) to give the oxazolidin-2-
one (rac)-anti-40 (19 mg, 4%) as a white crystalline solid; RF [light
petroleum (40–60 °C)/diethyl ether (1:1)] 0.51; mp 122–124 °C;
mmax (CHCl3) cmꢀ1 1778 (OC@O) and 1701 (NC@O); dH (400 MHz;
CDCl3) 7.70 (1H, s, CH; Ar), 7.68 (2H, dd, J 8.4 and 2.7, 2 ꢃ CH; Ar-
OCH3), 7.46 (1H, dd, J 8.7 and 1.6, Ar), 7.13 (1H, dd, J 8.7 and 1.7,
CH; Ar), 7.09 (1H, s, CH; Ar), 5.28 (1H, q, J 6.9, ArCHCH3), 4.36–
4.31 (1H, dt, J 9.1 and 3.2, i-PrCHN), 4.10 (1H, dd, J 9.1 and 3.2,
CHAHBO), 4.05 (1H, t, J 9.1, CHAHBO), 3.88 (3H, s, CH3O), 2.50–
2.39 (1H, m, CH(CH3)2), 1.57 (3H, d, J 6.9, ArCHCH3), 0.91 (3H, d, J
6.9, CHACHCHB) and 0.90 (3H, d, J 6.9, CHACHCHB); dC (100 MHz;
C
23H22NO4 requires MH+, 376.1543); and the oxazolidin-2-one
(rac)-syn-9 (0.32 g, 62%) as a white solid; RF [light petroleum ether
(bp 40–60 °C)/diethyl ether (1:1)] 0.33; mp 137–139 °C; mmax
(CHCl3) cmꢀ1 1780 (OC@O) and 1699 (NC@O); dH (400 MHz;
CDCl3) 7.60 (1H, d, J 8.4, CH; Ar), 7.51 (1H, br d, J 8.4, CH; Ar),
7.33 (1H, s, CH; Ar), 7.29–7.24 (3H, m, 3 ꢃ CH; Ph), 7.15–7.10
(2H, m, 2 ꢃ CH; Ph), 6.91 (2H, br d, J 7.0, 2 ꢃ CH; Ar), 5.46 (1H,
dd, J 8.9 and 5.2, PhCHN), 5.20 (1H, q, J 6.9, ArCHCH3), 4.60 (1H,
t, J 9.1, CHAHBO), 4.03 (1H, dd J 8.9 and 5.2, CHAHBO), 3.92 (3H, s,
CH3O) and 1.44 (3H, d, J 6.9, ArCHCH3); dC (100 MHz; CDCl3)
173.6 (NC@O), 157.6 (i-CO; Ar), 153.0 (OC@O), 138.2, 135.1,
133.6 and 128.8 (4 ꢃ i-C; Ar and Ph), 129.4, 127.0, 126.4, 126.3,
118.7 and 105.5 (6 ꢃ CH; Ar), 128.8,2 127.21 and 125.92 (5 ꢃ CH;
Ph), 69.5 (CH2O), 57.8 (PhCHN), 55.3 (CH3O), 43.8 (ArCHCH3) and
18.7 (ArCHCH3) (Found MH+, 376.1553; C23H22NO4 requires MH+,
376.1543).
3
3
3
3
CDCl3) 174.7 (NC@O), 157.6 (i-C-O; Ar), 153.7 (OC@O), 135.4,
133.8 and 128.8 (3 ꢃ i-C; Ar), 129.3, 127.0, 126.8, 126.6, 118.8
and 105.5 (6 ꢃ CH; Ar), 63.0 (CH2O), 59.0 (i-PrCHN), 55.2 (OCH3),
42.8 (ArCHCH3), 28.5 (CH(CH3)2), 19.6 (CHA3 CHCH3B), 17.9
(CHA3 CHCH3B) and 14.6 (ArCHCH3) (Found MH+, 342.1707;
4.44. Synthesis of ethyl 3-[2-(6-methoxynaphthalene-2-yl)-
propanoyl]-oxazolidin-2-one 4-carboxylate (rac)-anti-52
and ethyl 3-[2-(6-methoxynaphthalene-2-yl)propanoyl]-
oxazolidin-2-one 4-carboxylate (rac)-syn-52
C
20H24NO4 requires MH+, 342.1700); and the oxazolidin-2-one
In the same way as the oxazolidin-2-one (rac)-20, n-BuLi
(0.6 mL, 2.5 M in hexane, 1.50 mmol), oxazolidin-2-one (rac)-14
(0.21 g, 1.36 mmol) and the pentafluorophenyl 2-(6-methoxy-
naphthalene-2-yl)propanoate (rac)-6 (0.59 g, 1.50 mmol), gave a
separable mixture of two diastereoisomeric oxazolidin-2-ones 52
(ratio: 97:3 syn-:anti-). The crude residue was purified by flash
column chromatography on a silica gel [light petroleum ether
(bp 40–60 °C)/diethyl ether (7:3)] to give the oxazolidin-2-one
(rac)-anti-52 (9 mg, 2%) as a colourless oil; RF [light petroleum
ether (bp 40–60 °C)/diethyl ether (1:1)] 0.28; mmax (CHCl3) cmꢀ1
1791 (OC@O), 1751 (CC@O) and 1705 (NC@O); dH (400 MHz;
CDCl3) 7.72 (1H, s, CH; Ar), 7.67 (2H, dd, J 8.4 and 2.6, 2 ꢃ CH;
Ar), 7.44 (1H, dd, J 8.4 and 2.6, CH; Ar), 7.11 (1H, dd, J 8.4 and
2.6, CH; Ar), 7.07 (1H, s, CH; Ar), 5.24 (1H, q, J 6.9, ArCHCH3),
(rac)-syn-40 (0.25 g, 54%) as a white crystalline solid; RF [light
petroleum ether (bp 40–60 °C)/diethyl ether (1:1)] 0.34; mp 92–
94 °C; mmax (CHCl3) cmꢀ1 1778 (OC@O) and 1701 (NC@O); dH
(400 MHz; CDCl3) 7.72 (1H, br d, J 1.7, CH; Ar), 7.69 (2H, dd, J 8.6
and 2.5, 2 ꢃ CH; Ar), 7.45 (1H, dd, J 8.6 and 1.8, CH; Ar), 7.13
(1H, dd, J 8.6 and 1.8, CH; Ar), 7.09 (1H, s, CH; Ar), 5.26 (1H, q, J
6.9, ArCHCH3), 4.52–4.46 (1H, dt, J 8.9 and 3.2, i-PrCHN), 4.21
(1H, t, J 8.9, CHAHBO), 4.06 (1H, dd, J 8.9 and 3.2, CHAHBO), 3.88
(3H, s, CH3O), 2.25–2.13 (1H, m, CH(CH3)2), 1.53 (3H, d, J 6.9,
ArCHCH3), 0.75 (3H, d, J 6.9, CHACHCHB) and 0.38 (3H, d, J 6.9,
3
3
CHACHCHB); dC (100 MHz; CDCl3) 174.6 (NC@O), 157.6 (i-C-O;Ar),
3
3
153.5 (OC@O), 135.7, 133.7 and 128.9 (3 ꢃ i-C; Ar), 129.4, 127.0,
126.7, 126.6, 118.8 and 105.5 (6 ꢃ CH; Ar), 62.9 (CH2O), 58.1