The benzamide conical vial was further rinsed with an addi-
tional amount of THF (0.5 mL). After 1 h, Se powder (81 mg,
1.02 mmol) was added under an inverse argon funnel and the
reaction was warmed to 0 ЊC. After 1 h or until the solution was
homogeneous, cinnamyl bromide (220 mg, 0.17 mL, 1.12
mmol) was added. After 1 h, the reaction was quenched with
sat. aq. NH4Cl (20 mL) and extracted with Et2O (3 × 75 mL).
The dried (MgSO4) organic layer was concentrated in vacuo and
the residue was purified by chromatography on silica gel, elut-
ing with 2–20% EtOAc/hexane. The final product was recrystal-
lized in hexane to give 58 (300 mg, 54%) as a yellow solid: mp
2H), 1.54 (d, J = 6.3 Hz, 3H); 13C NMR (75 MHz, CDCl3)
δ 164.7, 164.2, 150.6, 136.9, 136.6, 135.9, 133.2, 131.4, 130.9,
130.4, 128.7, 128.4, 127.7, 126.4, 126.3, 124.9, 123.6, 74.1, 71.0,
68.8, 28.8, 17.2, 14.4; HRMS (FABϩ) calcd. for C27H25N2O5-
80Se (M ϩ Hϩ) 537.0929. Found 537.0942.
(1S )-{2-[2-(3-Phenyl-(E )-allylselanyl)-phenyl]-4,5-dihydro-
oxazol-4R-yl}-ethanol (60)
To a stirred solution of seleno-ester 81 (37 mg, 0.070 mmol) in
MeOH (0.3 mL) at rt was added K2CO3 (2.0 mg, 0.010 mmol).
After 30 min, the reaction was quenched with sat. aq. NH4Cl
(3 mL) and extracted with EtOAc (3 × 20 mL), The dried
(MgSO4) organic layer was concentrated in vacuo and the
residue purified by chromatography on silica gel, eluting with
2–40% EtOAc/hexane to give 60 (13 mg, 50%) as a white solid:
23
59–63 ЊC; [α]D Ϫ8.0 (c 6.50, CHCl3). IR (neat) 2941, 1644,
1
1464 cmϪ1; H NMR (300 MHz, CDCl3) δ 7.82 (dd, J = 1.6,
7.5 Hz, 1H), 7.49 (d, J = 7.9 Hz, 1H), 7.18–7.38 (m, 7H), 6.64
(d, J = 15.6 Hz, 1H), 6.40 (dt, J = 7.5, 15.0 Hz, 1H), 4.67 (dt,
J = 4.5, 4.7 Hz, 1H), 4.55 (dd, J = 6.9, 8.6 Hz, 1H), 4.44 (dd,
J = 4.5, 6.2 Hz, 1H), 4.35 (dd, J = 8.7, 9.9 Hz, 1H), 3.73 (d,
23
mp 100 ЊC; [α]D Ϫ5.7 (c 1.20, CHCl3); IR (neat) 3445, 1644,
1
1472 cmϪ1; H NMR (300 MHz, CDCl3) δ 7.84 (dd, J = 1.5,
J = 7.5, 2H), 1.18 (d, J = 6.2 Hz, 3H), 1.00–1.10 (m, 21H); 13
C
7.7 Hz, 1H), 7.52 (d, J = 7.8 Hz, 1H), 7.20–7.40 (m, 7H), 6.61
(d, J = 15.7 Hz, 1H), 6.41 (dt, J = 7.4, 15.1 Hz, 1H), 4.38–4.42
(m, 3H), 4.11–4.19 (m, 1H), 3.73 (d, J = 7.5 Hz, 2H), 2.05 (br s,
1H), 1.24 (d, J = 6.5 Hz, 3H); 13C NMR (75 MHz, CDCl3)
δ 164.7, 136.9, 135.9, 133.3, 131.2, 130.2, 129.0, 128.7, 127.7,
126.5, 125.2, 124.9, 73.0, 68.1, 67.5, 29.4, 18.8, 14.4; HRMS
(FABϩ) calcd. for C20H21NO278Se (M ϩ Hϩ) 386.0824. Found
386.0827.
NMR (75 MHz, CDCl3) δ 164.0, 137.1, 136.3, 133.2, 131.0,
130.4, 128.7, 128.3, 127.6, 127.0, 126.4, 125.2, 124.8, 72.3,
68.9, 67.7, 28.8, 18.3, 17.7, 12.5; HRMS (FABϩ) calcd. for
C29H42NO280SeSi (M ϩ Hϩ) 544.2150. Found 544.2147.
1R-{2-[2-(3-Phenyl-allylselanyl)-phenyl]-4,5-dihydro-oxazol-
(4R)-yl}-ethanol (59)
To a stirred solution of selenide 58 (41 mg, 0.10 mmol) in THF
(0.8 mL) at rt was added acetic acid (15 mg, 13 µL, 0.2 mmol)
and TBAF (1.9 mL, 1.9 mmol, 1 M in THF). After 1 h, the
reaction was quenched with sat. aq. NH4Cl (10 mL) and
extracted with EtOAc (3 × 25 mL). The dried (MgSO4) organic
layer was concentrated in vacuo and the residue was purified by
chromatography over silica gel, eluting with 2–60% EtOAc/hex-
2-(2-Bromo-phenyl)-4,5-dihydro-oxazole-(4S )-carboxylic acid
methyl ester (61)
To a stirred solution of 50 (1.24 g, 4.10 mmol) in CH2Cl2 (35
mL) at Ϫ78 ЊC was added DAST (726 mg, 0.6 mL, 4.50 mmol)
dropwise over 15 min. After 1 h, the slurry was quenched with
K2CO3 (851 mg, 6.20 mmol) and warmed to rt. After 20 min,
sat. aq. NaHCO3 (20 mL) was added and extracted with Et2O
(3 × 75 mL). The dried (MgSO4) organic layer was concentrated
in vacuo and the residue was purified by chromatography on
silica gel to give 61 (1.06 g, 91%) as a light pink oil: [α]D23 ϩ33.2
(c 1.31, CHCl3); IR (neat) 2952, 1731, 1651 cmϪ1; 1H NMR (300
MHz, CDCl3) δ 7.70 (dd, J = 1.9, 6.9 Hz, 1H), 7.62 (dd, J = 1.2,
7.3 Hz, 1H), 7.23–7.34 (m, 2H), 4.99 (dd, J = 8.0, 10.8 Hz, 1H),
4.71 (dd, J = 8.2, 16.9 Hz, 1H), 4.62 (dd, J = 8.6, 10.6 Hz, 1H),
3.78 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 171.4, 166.0, 134.0,
132.3, 131.8, 128.3, 127.3, 122.0, 69.9, 68.8, 52.9; HRMS
(FABϩ) calcd. for C11H10NO3Br (M ϩ Hϩ) 282.9844. Found
283.9922.
23
ane to yield 59 (52 mg, 78%) as a white solid: mp 105 ЊC; [α]D
1
Ϫ11.7 (c 0.50, CHCl3); IR (neat) 3445, 1644, 1472 cmϪ1; H
NMR (300 MHz, CDCl3) δ 7.84 (dd, J = 1.5, 7.7 Hz, 1H), 7.52
(d, J = 7.8 Hz, 1H), 7.20–7.40 (m, 7H), 6.64 (d, J = 15.7 Hz, 1H),
6.43 (dt, J = 7.4, 15.1 Hz, 1H), 4.48 (dd, J = 7.4, 9.3 Hz, 1H),
4.30–4.37 (m, 1H), 4.23 (dd, J = 7.6 Hz, 2H), 3.70 (dd, J = 7.0,
7.9 Hz, 2H), 2.50 (br s, 1H), 1.36 (d, J = 6.5 Hz, 3H); 13C NMR
(75 MHz, CDCl3) δ 164.6, 136.9, 136.3, 133.3, 131.3, 130.4,
128.7, 128.7, 127.7, 126.7, 126.5, 125.1, 125.0, 73.4, 70.3, 69.6,
29.3, 20.3; HRMS (FABϩ) calcd. for C20H22NO280Se (M ϩ Hϩ)
388.0816. Found 388.0824.
4-Nitro-benzoic acid (1S )-{2-[2-(3-phenyl-(E )-allylselanyl)-
phenyl]-4,5-dihydro-oxazol-(4R)-yl}-ethyl ester (81)
1-[2-(2-Bromo-phenyl)-4,5-dihydro-oxazol-(4S )-yl]-2-methyl-
propan-1-one (62)
To a stirred solution 61 (2.22 g, 7.84 mmol) in THF (41 mL) at
Ϫ78 ЊC was added i-PrMgCl (9.4 mL, 9.4 mmol, 1 M in Et2O)
dropwise via syringe pump over 60 min. After 1.5 h, the slurry
was quenched with NH4Cl and extracted with Et2O (3 ×
250 mL). The dried (MgSO4) organic layer was concentrated
in vacuo and the residue was purified by chromatography on
To a stirred solution of selenide 59 (35 mg, 0.087 mmol) in THF
(0.72 mL) at Ϫ78 ЊC were added PPh3 (47 mg, 0.18 mmol) and
p-NO2C6H4CO2H (30 mg, 0.18 mmol). After 5 min, DEAD (31
mg, 28 µL, 0.18 mmol) was added dropwise to the reaction.
Over 2 h, the reaction was warmed slowly from Ϫ78 ЊC to rt.
After an additional 5 h at rt, the reaction was quenched with
sat. aq. NH4Cl (5 mL) and extracted with Et2O (3 × 50 mL).
The dried (MgSO4) organic layer was concentrated in vacuo
and the residue was purified by chromatography on silica gel,
eluting with 0.5–10% EtOAc/hexane to yield 81 (39 mg, 80%) as
23
silica gel to give 62 (1.72 mg, 74%) as a light pink oil: [α]D
1
ϩ28.4 (c 1.19, CHCl3). IR (neat) 2970, 1715, 1651 cmϪ1. H
NMR (300 MHz, CDCl3) δ 7.70 (dd, J = 1.9, 7.3 Hz, 1H), 7.66
(dd, J = 1.4, 7.4 Hz, 1H), 7.26–7.37 (m, 2H), 5.06 (dd, J = 7.4,
10.5 Hz, 1H), 4.82 (dd, J = 7.4, 8.5 Hz, 1H), 4.52 (dd, J = 8.9,
10.9 Hz, 1H), 3.25–3.35 (m, 1H), 1.27 (d, J = 7.2 Hz, 3H), 1.15
(d, J = 6.7 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 211.8, 164.6,
134.2, 132.1, 131.5, 129.2, 127.3, 122.1, 73.8, 68.5, 38.4, 18.8,
17.7; HRMS (FABϩ) calcd. for C13H15NO279Br (M ϩ Hϩ)
296.0286. Found 296.0299.
23
a white solid: mp 97–99 ЊC; [α]D ϩ18.4 (c 0.50, CHCl3); IR
(neat) 1723, 1645, 1525, 1272 cmϪ1 1H NMR (300 MHz,
;
1-[2-(2-Bromo-phenyl)-4,5-dihydro-oxazol-(4S )-yl]-2-methyl-
propan-(1R/S )-ol (63 and 64)
CDCl3) δ 8.11–8.19 (m, 4H), 7.80–7.83 (dd, J = 1.1, 7.9 Hz, 1H),
7.44 (d, J = 8.0 Hz, 1H), 7.20–7.37 (m, 7H), 6.58 (d, J = 15.5 Hz,
1H), 6.31 (dt, J = 7.8, 15.5 Hz, 1H), 5.30–5.37 (m, 1H), 4.52–4.62
(m, 1H), 4.40–4.50 (dt, J = 8.8, 17.9 Hz, 2H), 3.67 (d, J = 7.4 Hz,
To a stirred solution of 62 (250 mg, 0.9 mmol) in MeOH (3 mL)
at rt was added NaBH4 (38 mg, 1 mmol) in portions. After
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2, 1 3 1 5 – 1 3 2 9
1326