(3 × 30 mL). The combined organic extract was dried (MgSO4)
and concentrated. The residue was chromatographed to give
methyl 2-benzoyltetradecanoate 4a (2.70 g, 78% yield) as an
1H), 3.32 (d, J ) 7.5 Hz, 2H), 1.12 (d, J ) 6.4 Hz, 3H), 1.02 (d,
J ) 6.4 Hz, 3H); 13C NMR δ u: 192.9, 167.3, 136.9, 134.7, 33.1
d: 131.9, 127.4, 127.1, 126.9, 125.0, 67.5, 55.0, 19.9, 19.8; IR
1730, 1679, 1597, 1495 cm-1; HRMS calcd for C17H16O3 296.3660,
obsd 296.3663. Anal. Calcd for C17H16O3: C, 77.00; H, 6.80.
Found: C, 77.07; H, 6.89.
1
oil: TLC Rf ) 0.31 (95% H/EtOAc). H NMR δ 7.97 (d, J ) 8.5
Hz, 2H), 7.56 (t, J ) 8.5 Hz, 1H), 7.48 (t, J ) 8.5 Hz, 2H), 4.35
(t, J ) 6.9 Hz, 1H), 3.68 (s, 3H), 2.03 (m, 2H), 1.25 (bs, 20H)
0.88 (t, J ) 6.6 Hz, 3H); 13C NMR δ u: 193.5, 169.0, 131.9, 50.9,
30.3, 28.1, 28.0, 27.9, 27.8, 27.6, 26.1, 21.1 d: 131.9, 127.2, 127.0,
52.5, 12.6; IR 1744, 1689, 1597, 1581, 1448 cm-1; HRMS calcd
tert-Butyl 2-benzoylhydrocinnamate 4i (2.10 g, 67% yield) as
1
an oil:9 TLC Rf ) 0.30 (95% H/EtOAc); H NMR δ 7.95 (d, J )
8.4 Hz, 2H), 7.53 (d, J ) 7.3 Hz, 1H), 7.43 (t, J ) 8.4 Hz, 2H),
7.17-7.26 (m, 5H), 4.51 (t, J ) 7.2 Hz, 1H), 3.29 (d, J ) 7.2 Hz,
2H), 1.28 (s, 9H); 13C NMR δ u: 193.3, 166.9, 137.1, 134.9, 80.5,
33.0 d: 131.8, 127.5, 127.1, 127.0, 125.0, 55.7, 26.2; IR 1728,
1686, 1597, 1495 cm-1; HRMS calcd for C20H22O3 310.3929, obsd
310.3930. Anal. Calcd for C20H22O3: C, 77.39; H, 7.14. Found:
C, 77.45; H, 7.19.
for C22H34O3 346.5102, obsd 346.5114. Anal. Calcd for C22
H34O3: C, 76.26; H, 9.89. Found: C, 76.30; H, 9.96.
-
Methyl 2-benzoylundecanoate 4b (2.65 g, 87% yield) as an
1
oil: TLC Rf ) 0.29 (95% H/EtOAc); H NMR δ 7.98 (d, J ) 7.2
Hz, 2H), 7.59 (t, J ) 7.2 Hz, 1H), 7.48 (t, J ) 7.2 Hz, 2H), 4.33
(t, J ) 7.2 Hz, 1H), 3.67 (s, 3H), 2.00 (m, 2H), 1.24 (s, 14H),
0.87 (t, J ) 6.4 Hz, 3H); 13C NMR δ u: 193.6, 169.0, 134.7, 50.8,
30.3, 27.9, 27.8, 27.7, 27.6, 26.1, 21.1 d: 131.9, 127.2, 127.1,
127.0, 126.5, 52.4, 12.5; HRMS calcd for C19H28O3 304.4295, obsd
304.4297. Anal. Calcd for C19H28O3: C, 74.96; H, 9.27. Found:
C, 74.99; H, 9.29.
Diazo Transfer. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU,
0.153 mL, 1.0 mmol) was added over 30 min to a solution of the
benzoylated ester (4a, 346 mg, 1 mmol) and 4-acetoamidoben-
zenesulfonyl azide (248 mg, 1.0 mmol) in 10 mL of dry CH3CN
at 0 °C. After the initial exotherm had subsided, additional
4-acetoamidobenzenesulfonyl azide (124 mg, 0.5 mmol) and DBU
(0.076 mL, 0.5 mmol) were added over 30 min. After an
additional 30 min, the mixture was partitioned between water
and EtOAc (3 × 30 mL). The combined organic extract was dried
(MgSO4) and concentrated. The residue was chromatographed
to give methyl 2-diazotetradecanoate 2a (228 mg, 85% yield) as
a yellow oil:1 TLC Rf ) 0.37 (95% H/EtOAc); 1H NMR δ 3.76 (s,
3H), 2.30 (t, 2H, J ) 7.4 Hz), 1.53-1.44 (m, 2H), 1.25 (s, 20 H),
0.88 (t, J ) 6.6 Hz, 3H); 13C NMR δ u: 168.0, 31.9, 29.6, 29.5,
29.3, 29.2, 29.0, 28.7, 27.5, 23.0, 22.6 d: 51.7, 14.0; IR 1702, 1698,
1438 cm-1; HRMS calcd for C15H28O2N2 268.3995 (240.3861 loss
N2), obsd 240.3862. Anal. Calcd for C15H28O2N2: C, 67.13; H,
10.52. Found: C, 67.15; H, 10.55.
Methyl 2-diazoundecanoate 2b (179 mg, 79% yield) as a yellow
oil:5 TLC Rf ) 0.35 (95% H/EtOAc); 1H NMR δ 3.76 (s, 3H), 2.30
(t, 2H, J ) 7.4 Hz), 1.53-1.44 (m, 2H), 1.25 (s, 12H), 0.88 (t, J
) 6.6 Hz, 3H); 13C NMR δ u: 166.5, 30.3, 27.9, 27.7, 27.2, 26.0,
21.4, 21.1 d: 50.2, 12.5; HRMS calcd for C12H22O2N2 226.3189
(198.3055 loss N2), obsd 198.3056. Anal. Calcd for C12H22O2N2:
C, 63.69; H, 9.80. Found: C, 63.72; H, 9.88.
Methyl 2-diazooctanoate 2c (151 mg, 82% yield) as a yellow
oil. TLC: Rf ) 0.32 (95% H/EtOAc); 1H NMR δ 3.76 (s, 3H), 2.30
(t, 2H, J ) 7.4 Hz), 1.49 (m, 2H), 1.32 (m, 6H), 0.89 (t, J ) 6.6
Hz, 3H); 13C NMR δ u: 29.9, 26.8, 26.0, 21.5, 21.0 d: 50.3, 12.5;
HRMS calcd for C9H16O2N2 184.2382 (156.2248 loss N2), obsd
156.2252. Anal. Calcd for C9H16O2N2: C, 58.67;, H, 8.75.
Found: C, 58.68; H, 8.77.
Methyl 2-diazoheptanoate 2d (143 mg, 84% yield) as a yellow
oil: TLC Rf ) 0.30 (95% H/EtOAc); 1H NMR δ 3.75 (s, 3H), 2.30
(t, 2H, J ) 7.4 Hz), 1.53-1.42 (m, 2H), 1.25 (s, 4H), 0.86 (t, J )
6.6 Hz, 3H); 13C NMR δ u: 168.1, 31.9, 29.1, 22.0, 21.5, d: 52.3,
14.3; HRMS calcd for C8H14O2N2 170.2114 (142.1980 loss N2),
obsd 142.1981. Anal. Calcd for C8H14O2N2: C, 56.45; H, 8.29.
Found: C, 56.49; H, 8.37.
Methyl 2-diazohexanoate 2e (151 mg, 84% yield) as a yellow
oil: TLC Rf ) 0.28 (95% H/EtOAc); 1H NMR δ 3.76 (s, 3H), 2.31
(t, 2H, J ) 7.4 Hz), 1.58-1.31 (m, 4H), 0.93 (t, J ) 6.6 Hz, 3H);
13C NMR δ u: 28.1, 21.2, 20.3, d: 50.3, 12.1; HRMS Calcd for
C7H12O2N2 156.1845 (128.1711 loss N2), obsd 128.1716. Anal.
Calcd for C7H12O2N2: C, 53.83; H, 7.74. Found: C, 53.88; H,
7.81.
Methyl 2-diazohydrocinnamate 2f (160 mg, 84% yield) as a
yellow oil:7 TLC Rf ) 0.31 (95% H/EtOAc); 1H NMR δ 7.22-
7.35 (m, 5H), 3.78 (s, 3H), 3.63 (s, 2H); 13C NMR δ u: 164.2,
135.6, 27.8 d: 127.3, 126.8, 126.4, 125.6, 50.5; IR 1730, 1598,
1495, 1453 cm-1; HRMS calcd for C10H10O2N2 190.2016 (162.1882
loss N2), obsd 162.1884. Anal. Calcd for C10H10O2N2: C, 63.15;
H, 5.30. Found: C, 63.17; H, 5.37.
Ethyl 2-diazohydrocinnamate 2g (165 mg, 81% yield) as a
yellow oil:7 TLC Rf ) 0.33 (95% H/EtOAc); 1H NMR δ 7.22-
7.35 (m, 5H), 4.24 (q, J ) 7.2 Hz, 2 H) 3.63 (s, 2H), 1.28 (d, J )
7.2 Hz, 3H); 13C NMR δ u: 163.3, 135.7, 59.4, 27.8 d: 127.2,
126.8, 126.4, 125.6, 13.0; HRMS calcd for C11H12O2N2 204.2285
Methyl 2-benzoyloctanoate 4c (2.20 g, 84% yield) as an oil:
1
TLC Rf ) 0.27 (95% H/EtOAc); H NMR δ 7.98 (d, J ) 7.2 Hz,
2H), 7.59 (t, J ) 7.2 Hz, 1H), 7.49 (t, J ) 7.2 Hz, 2H), 4.33 (t, J
) 7.2 Hz, 1H), 3.68 (s, 3H), 2.00 (m, 2H), 1.29 (s, 8H) 0.86 (t, J
) 6.4 Hz, 3H); 13C NMR δ u: 193.7, 169.0, 134.7, 50.8, 29.9,
27.6, 27.5, 26.0, 20.9 d: 132.0, 127.2, 127.1, 127.0, 52.5, 12.5;
HRMS calcd for C16H22O3 262.3489, obsd 262.3490. Anal. Calcd
for C16H22O3: C, 73.25; H, 8.45. Found: C, 73.28; H, 8.46.
Methyl 2-benzoylheptanoate 4d (2.31 g, 93% yield) as an oil:
1
TLC Rf ) 0.25 (95% H/EtOAc); H NMR δ 7.99 (d, J ) 7.2 Hz,
2H), 7.58 (t, J ) 7.2 Hz, 1H), 7.49 (t, J ) 7.2 Hz, 2H), 4.32 (t, J
) 7.2 Hz, 1H), 3.68 (s, 3H), 2.03 (m, 2H), 1.31 (s, 6H) 0.87 (t, J
) 6.4 Hz, 3H); 13C NMR δ u: 193.7, 169.0, 134.6, 50.9, 30.0,
27.5, 25.8, 20.8 d: 131.9, 127.2, 127.0, 52.5, 12.4; HRMS calcd
for C15H20O3 248.3220, obsd 248.3221. Anal. Calcd for C15
20O3: C, 72.55; H, 8.12. Found C, 72.56; H, 8.14.
Methyl 2-benzoylhexanoate 4e (2.11 g, 90% yield) as an oil:
-
H
1
TLC Rf ) 0.23 (95% H/EtOAc); H NMR δ 7.98 (d, J ) 7.2 Hz,
2H), 7.56 (t, J ) 7.2 Hz, 1H), 7.48 (t, J ) 7.2 Hz, 2H), 4.34 (t, J
) 7.2 Hz, 1H), 3.67 (s, 3H), 2.02 (m, 2H), 1.34 (s, 4H), 0.90 (t, J
) 6.4 Hz, 3H); 13C NMR δ u: 193.7, 168.9,134.6, 50.8, 28.2, 27.3,
21.0 d: 131.9, 127.2, 127.0, 52.4, 12.2; HRMS calcd for C14H18O3
234.2951, obsd 234.2996. Anal. Calcd for C14H18O3: C, 71.77;
H, 7.74. Found C, 71.79; H, 7.79.
Methyl 2-benzoylhydrocinnamate 4f (2.28 g, 85% yield) as an
1
oil:6 TLC Rf ) 0.17 (95% H/EtOAc); H NMR δ 7.95 (d, J ) 8.4
Hz, 2H), 7.53 (d, J ) 7.3 Hz, 1H), 7.45 (t, J ) 8.4 Hz, 2H), 7.21-
7.25 (m, 5H), 4.65 (t, J ) 7.5 Hz, 1H), 3.64 (s, 3H), 3.32 (d, J )
7.5 Hz, 2H); 13C NMR δ u: 192.9, 168.2, 136.8, 134.6, 33.3 d:
132.1, 127.4, 127.2, 127.0, 125.2, 54.4, 51.0; IR 1739, 1686, 1596,
1495, 1448 cm-1; HRMS calcd for C17H16O3 268.3122, obsd
268.3123. Anal. Calcd for C17H16O3: C, 73.25; H, 8.45. Found:
C, 73.28; H, 8.46.
Representative Benzoylation Procedure by Method B.
Titanium tetrachloride (2.87 g, 15 mmol) was added over 30 min
to a solution of benzoyl chloride (4.26 g, 30 mmol), 1g (1.78 g,
10 mmol), and triethylamine (6.13 g, 60 mmol) in 10 mL of dry
CH3CN at 0 °C. The mixture was warmed to reflux for 15 min.
The mixture was cooled and then partitioned between water and
EtOAc (3 × 30 mL). The combined organic extract was dried
(MgSO4) and concentrated. The residue was chromatographed
to give ethyl 2-benzoylhydrocinnamate 4g (2.14 g, 78% yield)
as an oil:8 TLC: Rf ) 0.22 (95% H/EtOAc); 1H NMR δ 7.96 (d, J
) 8.4 Hz, 2H), 7.53 (d, J ) 7.3 Hz, 1H), 7.43 (t, J ) 8.4 Hz, 2H),
7.21-7.25 (m, 5H), 4.63 (t, J ) 7.3 Hz, 1H), 4.08 (q, J ) 7.1 Hz,
2H), 3.32 (d, J ) 7.3 Hz, 2H), 1.10 (t, J ) 7.1 Hz, 3H); 13C NMR
δ u: 192.9, 167.7, 136.9, 134.6, 59.9, 33.2 d: 132.0, 127.4, 127.1,
126.9, 125.1, 54.6, 12.4; IR 1736, 1687, 1597, 1495 cm-1; HRMS
calcd for C18H18O3 282.3391, obsd 283.3398. Anal. Calcd for
C18H18O3: C, 76.57; H, 6.43. Found: C, 76.61; H, 6.54.
Isopropyl 2-benzoylhydrocinnamate 4h (2.01 g, 68% yield) as
1
an oil: TLC Rf ) 0.26 (95% H/EtOAc). H NMR δ 7.96 (d, J )
8.4 Hz, 2H), 7.53 (d, J ) 7.3 Hz, 1H), 7.43 (t, J ) 8.4 Hz, 2H),
7.21-7.25 (m, 5H), 4.94 (m, J ) 7.5 Hz, 1 H) 4.63 (t, J ) 7.5 Hz,
J. Org. Chem, Vol. 70, No. 7, 2005 2853