Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
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NMR (CDCl3) d 28.14, 33.78, 34.43, 80.08 (OCMe3),
123.50 (CHvCHCO), 126.10, 128.30, 128.44, 140.97,
146.74 (CvCHCO), 165.96 (CvO); IR (CH2Cl2): 3029,
3004, 2977, 1701, 1648, 1365, 1297, 1114 cm21; MS (m/
z) (40 eV): 176 (M12C4H8, 18), 159 (18), 130 (12), 91
(100), 65 (8); HRMS Calcd for C11H12O2 m/z 176.0837,
found: 176.0833.
(CvO), 1437, 1286, 1117, 1105, 1044, 724 cm21; MS
(m/z): 206 (M1, 5), 175 (18), 161 (20), 146 (21), 135 (40),
117 (20), 100 (30), 91 (100), 84 (20), 71 (18); HRMS Calcd
for C12H14O3 m/z 206.0943, found: 206.0944.
(Z)-4-Benzyloxycrotonic acid methyl ester (5ga-Z).
Colorless oil; H NMR (CDCl3) d 3.70 (s, 3H, OCH3),
1
4.55 (s, 2H) 4.65 (dd, J4.9, 2.3 Hz, 2H), 5.83 (dt,
J11.7, 2.3 Hz, 1H), 6.45 (dt, J11.7, 4.9 Hz, 1H), 7.25±
7.36 (m, 5H, aromatic-H); 13C NMR (CDCl3) d 51.25,
68.40, 72.84, 119.04, 127.72, 128.38, 137.86, 148.50,
166.36 (CvO); IR (CH2Cl2): 3031, 1719, 1641, 1436,
1202, 1092, 724 cm21; MS (m/z): 206 (M1, 5), 164 (35),
149 (45), 135 (100), 115 (32), 100 (70), 91 (77), 83 (32), 77
(30), 71 (20), 65 (30); HRMS Calcd for C12H14O3 m/z
206.0943, found: 206.0958.
5-Phenyl-2(E)-pentenal (5ff). Colorless oil; 1H NMR
(CDCl3) d 2.67 (q, J6.3 Hz, 2H), 2.84 (t, J8.5 Hz,
2H), 6.13 (dd, J15.5, 7.9 Hz, 1H), 6.86 (dt, J15.6,
6.3 Hz, 1H), 9.49 (d, J7.9 Hz, 1H); 13C NMR (CDCl3) d
34.17, 126.34, 128.28, 128.55, 133.37, 140.22, 157.21,
193.89; IR (CH2Cl2): 3063, 3030, 2931, 1686, 1490,
1121 cm21; Mass (m/z) (50 eV): 160 (M1, 8), 142 (5), 116
(20), 91 (100), 77 (6), 65 (16); HRMS Calcd for C17H16O
m/z 160.0888, found: 160.0895.
5-Benzyloxy-2(E)-pentenoic acid methyl ester (5ha-E).
Colorless oil; 1H NMR (CDCl3) d 2.48 (qd, J6.5,
1.4 Hz, 2H), 3.58 (t, J6.5 Hz, 2H), 3.72 (s, 3H), 4.52 (s,
2H), 5.90 (dt, J15.7, 1.5 Hz, 1H), 6.99 (dt, J15.7, 6.9 Hz,
1H), 7.29±7.39 (m, 5H, aromatic-H); IR (CH2Cl2): 3033,
1716 (CvO), 1652, 1436, 1320, 1274, 1179, 1106, 1034,
978, 741, 703 cm21; MS (m/z): 220 (M1, 2), 190 (3), 176
(3), 160 (17), 145 (4), 130 (8), 122 (18), 144 (21) 105 (20),
100 (79), 91 (100), 77 (6), 69 (28); HRMS Calcd for
C13H16O3 m/z 220.1099, found: 220.1109.
1,4-Diphenyl-1-butene (5fg-E and 5fg-Z). Benzylidene-
triphenylphosphorane (Ph3PvCHPh) was prepared from
the reaction of benzyltriphenylphosphonium bromide
(4289.9 mg, 9.9 mmol) and n-BuLi (6.2 mL, 1.6 M in
hexane) in 20 mL of THF at 2788C for 0.5 h. To a solution
of ozonide 2f, prepared from 4-phenyl-1-butene (1f)
(633.6 mg, 4.8 mmol), in 10 mL of THF was added the
THF solution of Ph3PvCHPh at 2788C and the reaction
was warmed slowly to ambient temperature. After 3 h, the
reaction mixture was concentrated and chromatographed on
a silica gel by elution with hexane to give a mixture of E-and
Z-ole®n 5fg (731.2 mg, 78% yield) as a colorless oil. The
E/Z ratio is approximately 5/2 and the Z-isomer is less polar
than E-isomer on TLC. Preparative TLC separated them
with hexane as a developing solvent.
5-Benzyloxy-2(Z)-pentenoic acid methyl ester (5ha-Z).
Colorless oil; 1H NMR (CDCl3) d 2.99 (qd, J6.3,
1.8 Hz, 2H), 3.60 (t, J6.3 Hz, 2H), 3.71 (s, 3H), 4.53 (s,
2H), 5.86 (dt, J11.5, 1.8 Hz, 1H), 6.35 (dt, J11.5, 3.6 Hz,
1H), 7.30±7.36 (m, 5H, aromatic-H); 13C NMR (CDCl3) d
29.55, 50.97, 68.98, 72.77, 120.56, 127.56, 128.31, 138.29,
147.05, 183.92 (CvO); IR (CH2Cl2): 2947, 1717 (CvO),
1652, 1439, 1322, 1273, 1179, 1104, 1034, 978, 740,
703 cm21; MS (m/z) (15 eV): 221 (M111, 3), 188 (35),
176 (18), 160 (76), 146 (23), 130 (36), 114 (98), 100 (56),
91 (100); HRMS Calcd for C13H16O3 m/z 220.1099, found:
220.1084.
1,4-Diphenyl-1(E)-butene (5fg-E). White solid, mp 31.5±
32.58C; H NMR (CDCl3) d 2.47±2.56 (m, 2H), 2.79 (t,
1
J7.2 Hz, 2H) 6.24 (dt, J16.0, 6.6 Hz, 1H, ±CHvCHPh),
6.41 (d, J16.0 Hz, 1H, ±CHvCHPh), 7.16±7.33 (m, 10H,
aromatic-H); 13C NMR (CDCl3) d 34.83, 35.86, 125.86,
125.97, 126.90, 128.34, 128.45, 129.94, 130.37,137.72,
141.73; IR (CH2CL2): 3082, 3060, 3025, 2929, 2855,
1598, 1488, 1446 cm21; MS (m/z): 208 (M1, 25), 117
(100), 91 (28), 77 (8) 65 (7); HRMS Calcd for C16H16 m/z
208.1253, found: 208.1252.
6-Benzyloxy-2(E)-hexenoic acid methyl ester (5ia-E).
1
Colorless oil; H NMR (CDCl3) d 1.73 (quint, J7.0 Hz,
2H), 2.30 (qd, J7.0, 1.4 Hz, 2H), 3.48 (t, J7.0 Hz, 2H),
3.71 (s, 3H), 4.49 (s, 2H, CH2Ph), 5.83 (dt, J15.7, 1.4 Hz,
1H), 6.97 (dt, J15.7, 7.0 Hz, 1H), 7.25±7.47 (m, 5H,
aromatic-H); 13C NMR (CDCl3) d 28.08, 28.89, 51.35,
69.17, 72.91, 121.18, 127.56, 128.34, 148.89, 167.05
(CvO); IR (CH2Cl2): 3027, 2940, 1704 (CvO), 1647,
1430, 1262, 1201, 1086, 1038, 974, 733 cm21; MS (m/z):
234 (M1, 2), 220 (2), 202 (2), 188 (5), 174 (5), 160 (38), 145
(10), 130 (18), 121 (10), 114 (60), 100 (10), 91 (100);
HRMS Calcd for C14H18O3 m/z 234.1256, found: 234.1243.
1
1,4-Diphenyl-1(Z)-butene (5fg-Z). Colorless oil; H NMR
(CDCl3) d 2.61±2.68 (m, 2H), 2.74±2.81 (m, 2H), 5.69 (dt
J11.6, 6.7 Hz, 1H, ±CHvCHPh), 6.43 (d, J11.6 Hz,
1H, ±CHvCHPh), 7.15±7.49 (m, 10H, aromatic-H); 13C
NMR (CDCl3) d 30.40, 36.07, 125.91, 126.56, 128.14,
128.34, 128.46, 128.71, 129.43, 131.80, 137.57, 141.67;
IR (CH2Cl2): 3080, 3060, 3024, 2924, 2855, 1599, 1490,
1445, 1073, 1026, 962 cm21; MS (m/z): 208 (M1, 20),
180 (10), 117 (100), 91 (28), 77 (6), 65 (8); HRMS Calcd
for C16H16 m/z 208.1253, found: 208.1252.
6-Benzyloxy-2(Z)-hexenoic acid methyl ester (5ia-Z).
1
Colorless oil; H NMR (CDCl3) d 1.78 (quint, J6.6 Hz,
(E)-4-Benzyloxycrotonic acid methyl ester (5ga-E).
Colorless oil; H NMR (CDCl3) d 3.75 (s, 3H, OCH3),
2H), 2.75 (qd, J6.6, 1.7 Hz, 2H), 3.51 (t, J6.6 Hz, 2H),
3.70 (s, 3H), 4.50 (s, 2H), 5.79 (dt, J11.5, 1.7 Hz, 1H,
CvCH±CO), 6.26 (dt, J11.5, 6.6 Hz, 1H, CHvCH±
CO), 7.28±7.35 (m, 5H, aromatic-H); 13C NMR (CDCl3)
d 25.91, 29.11, 50.98, 69.78, 72.93, 119.56, 127.50,
127.61, 128.32, 138.49, 150.02, 166.76 (CvO); IR
(CH2Cl2): 2937, 1705 (CvO), 1645, 1432, 1261, 1205,
1
4.18 (dd, J4.2, 2.1 Hz, 2H), 4.57 (s, 2H, Ph±CH2), 6.15
(dt, J15.7, 2.1 Hz, 1H), 7.00 (dt, J15.7, 4.2 Hz, 1H),
7.29±7.37 (m, 5H, aromatic-H); 13C NMR (CDCl3) d
51.50, 68.47, 72.66, 120.82, 127.54, 127.74, 128.38,
137.60, 144.48, 166.66 (CvO); IR (CH2Cl2):3032, 1721