D. M. Hodgson et al. / Tetrahedron 60 (2004) 3611–3624
3621
2873w, 1715s, 1505s, 1368s, 1229m, 1167s, 1047s and
876m; dH (400 MHz) 5.61 (1H, d, J¼9 Hz, NH), 5.40 (1H,
m, vCH), 4.61 (1H, m, 7a-H), 4.25 (1H, m, 3a-H), 3.92–
3.80 (2H, m, 4-H and 5-H), 2.82 (1H, d, J¼11 Hz, OH), 2.20
(2H, t, J¼8 Hz, vCCH2), 1.47 (9H, s, OCMe3), 1.52–1.34
(4H, m, 2£CH2), 1.41 (3H, s, MeCO2), 1.34 (3H, s, MeCO2)
and 0.91 (3H, t, J¼7 Hz, Me); dC (100 MHz) 155.5 (CvO),
141.4 (vC), 121.3 (vCH), 110.1 (O2CMe), 79.8 (OCMe3),
76.0 (C3a), 73.7 (C7a), 68.5 (C5), 49.3 (C4), 34.1 (CH2),
29.6 (CH2), 28.4 (OCMe3), 28.2 (MeCO2), 26.5 (MeCO2),
22.4 (CH2) and 13.9 (CH2Me); m/z [CIþ(NH3)] 342
(MþHþ, 55%), 284 (100), 245(20), 228 (61) and 224 (35)
(Found: MþHþ, 342.2280. C18H32NO5 requires 342.2280).
4.2.2. 1,1-Dimethylethyl [(1R p,2S p)-3-butyl-2-hydroxy-
5-oxo-3-cyclohexen-1-yl]carbamate 30. (16 mg, 16%) as a
colourless liquid; Rf 0.50 (50% EtOAc–petrol); [a]2D3¼216
(c 1.0 in CHCl3); nmax(neat)/cm21 3364br s, 2960s, 2932s,
2873m, 1674s, 1504m, 1367m, 1283m, 1250m, 1164s,
1061w and 1017w; dH (400 MHz) 5.90 (1H, s, vCH), 5.00
(1H, d, J¼8 Hz, NH), 4.35 (1H, br s, CHOH), 4.20 (1H, m,
CHNHBoc), 2.65–2.52 (2H, m, CH2CvO), 2.38 (2H, t,
J¼7 Hz, vCCH2), 1.62–1.26 (4H, m, CH2CH2), 1.46 (9H,
s, OCMe3) and 0.94 (3H, t, J¼7 Hz, Me); dC (125 MHz)
196.8 (CvO), 165.0 (vC), 155.0 (CO2), 126.2 (vCH),
80.0 (OCMe3), 68.6 (CHOH), 50.2 (CHNH), 39.0
(CH2CvO), 34.5 (vCCH2), 29.0 (CH2), 28.3 (OCMe3),
22.3 (CH2) and 13.7 (Me); m/z [CIþ(NH3)] 301 (MþNHþ4 ,
18%), 284 (MþHþ, 42), 268 (30), 245 (100), 229 (70), 212
(35), 150 (40), 135 (60) and 79 (32).
(b, Table 1, entry 6) Epoxide 22 (100 mg, 0.353 mmol) was
added to a solution of BunLi (1.4 mol dm23 in hexanes;
0.90 cm3, 1.24 mmol, 3.5 equiv.) and bisoxazoline 4
(0.36 g, 1.24 mmol, 3.5 equiv.) in Et2O (3.5 cm3) at
278 8C. After 5 h at 278 8C the reaction was warmed to
0 8C (14 h), and gave, following standard work-up and
purification of the residue by column chromatography (50%
EtOAc–petrol), aminophenol 32 (49 mg, 52%, 69% based
on recovered epoxide 22).
(c, Table 1, entry 8) Epoxide 22 (100 mg, 0.353 mmol) was
added to a solution of BunLi (1.5 mol dm23 in hexanes;
0.80 cm3, 1.24 mmol, 3.5 equiv.) and sparteine 2 (0.28 cm3,
1.24 mmol, 3.5 equiv.) in toluene (3.5 cm3) at 278 8C.
After 5 h at 78 8C the reaction was quenched to give,
following standard work-up and purification of the residue
by column chromatography (50% EtOAc–petrol), amino
alcohol 29 (49 mg, 41%, 64% based on recovered epoxide
22). [a]2D3¼29 (c 1.0 in CHCl3). The ee of the 3,5-
dinitrobenzoate derivative (see Supporting information)
was determined to be 76% by chiral HPLC (OD column,
10% EtOH in heptane, 1.0 cm3 min21, tRmj, 10.5; tRmn,
14.2).
4.2.5. 1,1-Dimethylethyl (1R p,2R p,4S p,5S p)-8-aza-3-
oxatricyclo[3.2.1.02,4]-6-octene-8-carboxylate 23. Per-
acetic acid (38% w/v in acetic acid; 1.38 cm3, 7.77 mmol)
was added to a mixture of diene 3833 (1.0 g, 5.2 mmol),
NaOAc (20 mg) and Na2CO3 (1.6 g) in CH2Cl2 (20 cm3) at
0 8C. The reaction mixture was stirred for a total of 36 h,
with further peracetic acid (1.38 cm3) added over this
period. CH2Cl2 (10 cm3) and 1 M HCl (5 cm3) were then
added and the aqueous layer was extracted with CH2Cl2
(3£20 cm3). The organic extracts were combined, washed
with saturated aqueous NaHCO3 (10 cm3) and brine, dried
(MgSO4) and the solvent evaporated under reduced
pressure. Purification of the residue by column chromato-
graphy (75% Et2O–petrol) gave epoxide 23 (0.83 g, 77%)
as a white solid; Rf 0.28 (50% Et2O–petrol); mp 108–
109 8C (from Et2O) (Found: C, 63.1; H, 7.25; N, 6.5.
C11H15NO3 requires C, 63.1; H, 7.25; N, 6.7%); nmax(KBr)/
cm21 1698s, 1380s, 1258s, 1172s, 1101s and 906m; dH
(400 MHz) 6.56–6.51 (2H, m, HCvCH), 4.71 (1H, d,
J¼2.0 Hz, CH), 4.58 (1H, dd, J¼2.0, 0.5 Hz, CH), 3.48 (2H,
2£d, J¼3.5 Hz, 2£CH–O) and 1.47 (9H, s, But); dC
(100 MHz) 156.1 (CvO), 138.2 and 138.0 (CvC), 80.1
(CMe3), 61.0 and 60.7 (2£CH–O), 57.1 and 56.7 (2£CH)
and 28.2 and 28.1 (3£Me); m/z (CI) 210 (MþHþ, 15%), 155
(12), 110 (15) and 80 (100) (Found: MþHþ, 210.1131.
C11H16NO3 requires 210.1130).
4.2.3. 1,1-Dimethylethyl (3aa,4b,7b,7aa)-5-butyl-
3a,4,7,7a-tetrahydro-2,2-dimethyl-1,3-benzodioxol-4,7-
imine-8-carboxylate 31. (7.5 mg, 7%) as a colourless oil;
Rf 0.41 (20% EtOAc–petrol); nmax(neat)/cm21 2959s, 2933s,
2874w, 1709s, 1624w, 1368s, 1300m, 1160s, 1102m, 1063s
and 859w; dH (400 MHz, 2 rotamers observed) 5.82 and
5.75 (1H, two m, vCH), 4.62 and 4.55 (1H, two m, CHN),
4.48 and 4.36 (1H, two m, CHN), 4.27 (2H, dd, J¼15, 5 Hz,
3a,7a-H), 2.20–2.05 (2H, m, vCCH2), 1.47 (3H, s,
MeCO2), 1.45 (9H, s, Me3CO), 1.29 (3H, s, MeCO2),
1.50–1.25 (4H, m, CH2CH2), 1.29 (3H, s, MeCO2) and 0.88
(3H, br t, J¼7 Hz, Me); m/z [CIþ(NH3)] 324 (MþHþ, 55),
224 (100), 123 (35), 100 (28) and 90 (80) (Found: MþHþ,
324.2176. C18H30NO4 requires 324.2175).
4.2.4. 1,1-Dimethylethyl (3-butyl-2-hydroxyphenyl)car-
bamate 32. (9 mg, 10%) as a colourless oil; Rf 0.54 (20%
EtOAc–petrol); nmax(neat)/cm21 3322br m, 2957s, 2930s,
2871w, 1683s, 1526s, 1480s, 1368m, 1283m, 1246m, 1159s,
1067m, 866w and 770w; dH (400 MHz) 8.2 (1H, br s, OH),
6.96 (1H, dd, J¼7, 2 Hz, 4-H), 6.85 (1H, dd, J¼8, 2 Hz, 6-H),
6.79 (1H, dd, J¼8, 7 Hz, 5-H), 6.62 (1H, br s, NH), 2.67
(2H, t, J¼8 Hz, CH2), 1.64–1.56 (2H, m, CH2), 1.54 (9H, s,
OCMe3), 1.38 (2H, sxt, J¼7 Hz, CH2) and 0.94 (3H, t,
J¼7 Hz, Me); dC (100 MHz) 155.3 (CvO), 146.1
(vCOH), 132.8 (¼CCH2), 126.6 (C4), 125.3 (vCNH),
120.1 (C6), 119.6 (C5), 82.1 (OCMe3), 32.1 (CH2), 30.2
(CH2), 28.2 (OCMe3), 22.7 (CH2) and 14.0 (CH2); m/z (EI)
266 (MþHþ, 20%), 265 (Mþ, 100), 238 (15) and 225 (22);
m/z [CIþ(NH3)] 283 (MþNHþ4 , 48%), 266 (MþHþ, 100),
227 (75), 165 (37), 214 (100), 198 (95) and 170 (35) (Found:
MþHþ, 266.1752. C15H24NO3 requires 266.1756).
4.2.6. 1,1-Dimethylethyl [(1R p,2S p)-2-hydroxy-3-(1-
methylethyl)-3,5-cyclohexadien-1-yl]carbamate 39. (a)
Epoxide 23 (70 mg, 0.34 mmol) was added to a solution
of PriLi (1.4 mol dm23 in petrol; 0.50 cm3, 0.70 mmol) in
Et2O at 278 8C. After 5 h at 278 8C the reaction was
warmed to 0 8C (1 h), and gave, following standard work-up
and purification of the residue by column chromatography
(gradient elution, 30–50% Et2O–petrol) diene 39 (19 mg,
22%) as a clear colourless oil; Rf 0.40 (50% Et2O–petrol);
n
max(film)/cm21 3430br m, 2965s, 1694s, 1499s, 1367s, and
1167s; dH (500 MHz) 6.01–5.97 (1H, m, HCvCH), 5.75
(1H, d, J¼5.5 Hz, HCvCH), 5.56 (1H, dd, J¼9.5,