The Journal of Organic Chemistry
Note
m), 2.38 (3H, s), 2.38−2.33 (2H, m), 1.49 (2H, br s); 13C NMR (100
MHz, CDCl3): rotameric mixture: δ 144.3, 144.2, 144.0, 136.4, 134.8,
134.7, 133.8, 129.7, 127.5, 127.07, 127.06, 122.0, 121.9, 119.0, 56.9,
48.2, 21.8; LRMS (ESI+) m/z (rel intensity) 379.1 (1) [M + Na]+,
357.2 (1) [M + H]+, 340.1 (100); HRMS (ESI+) m/z calcd for
C20H25N2O2S [M + H]+: 357.1631. Found: 357.1644.
126.6, 118.9, 54.4, 46.5, 44.5; LRMS (ESI+) m/z (rel intensity) 202
(18) [M + H]+, 185 (26), 143 (84), 129 (59), 117 (36), 91 (100);
HRMS (ESI+) m/z calcd for C14H20N [M + H]+: 202.1590. Found:
202.1596.
Double Allylboration of Acid Anhydrides. To a round-bottom
flask equipped with a magnetic stirrer and charged with potassium
allyltrifluoroborate (0.370 g, 2.5 mmol, 5.0 equiv) were added CH2Cl2
(5 mL) and acid anhydride (0.50 mmol, 1.0 equiv). BF3·OEt2 (310 μL,
2.5 mmol, 5.0 equiv) was subsequently added dropwise, and the
mixture was stirred at room temperature under an N2 atmosphere.
After 2 h, starting material conversion was confirmed through TLC,
and approximately five drops of HCl (aq, 1 N) was added followed by
saturated NaHCO3 solution (5 mL). Deionized water (∼5−10 mL)
was added as necessary to facilitate phase separation, and the organic
phase was obtained. The aqueous phase was extracted with CH2Cl2 (3
× 5 mL), and the combined organic layers were dried over anhydrous
Na2SO4. After evaporation of the solvent, the crude mixture was
purified through silica gel flash chromatography.
(E)-4-Styrylhepta-1,6-dien-4-amine (2l). Using the standard nitrile
double allylboration procedure and flash chromatography on silica gel
EtOAc + 0.5% NEt3) afforded 2l (0.092 g, 44%) as a yellow oil. Rf =
0.23 (EtOAc); IR (thin film) νmax 3370, 3293, 3075, 3025, 3003, 2976,
2921, 2856, 1640, 1600, 1494, 1449, 1436, 1415, 1071, 997, 971, 915,
1
749, 693 cm−1; H NMR (400 MHz, CDCl3): δ 7.39−7.37 (2H, m),
7.33−7.29 (2H, m), 7.23−7.20 (1H, m), 6.49 (1H, d, J = 16.0 Hz),
6.27 (1H, d, J = 16.0 Hz), 5.80 (2H, dddd, J = 16.0, 9.5, 8.0, 6.5 Hz),
5.10−5.16 (4H, m), 2.36 (2H, dddd, J = 13.5, 6.5, 6.5, 1.0 Hz), 2.29−
2.24 (2H, m), 1.59 (2H, br s); 13C NMR (100 MHz, CDCl3): δ 137.4,
137.3, 134.0, 128.8, 128.1, 127.5, 126.5, 119.0, 55.7, 46.7; LRMS
(DART+) m/z (rel intensity) 214.2 (22) [M + H]+, 197.1 (100);
HRMS (DART+) m/z calcd for C15H20N [M + H]+: 214.1596. Found:
214.1592.
3,3-Diallylisobenzofuran-1(3H)-one (4a).6 Using the standard acid
anhydride double allylboration procedure and flash chromatography
on silica gel (30% EtOAc/hexanes) afforded 4a (0.099 g, 92%) as a
yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.86 (1H, ddd, J = 7.5, 1.0,
1.0 Hz), 7.60 (1H, ddd, J = 7.5, 7.5, 1.0 Hz), 7.50 (1H, ddd, J = 7.5,
7.5, 1.0 Hz), 7.38 (1H, ddd, J = 7.5, 1.0, 1.0 Hz), 5.60−5.49 (2H, m),
5.09−5.03 (4H, m), 2.76 (2H, dddd, J = 14.5, 7.5, 1.0, 1.0 Hz), 2.67
(2H, dddd, J = 14.0, 7.0, 1.0, 1.0 Hz); 13C NMR (100 MHz, CDCl3): δ
170.0, 151.8, 134.0, 130.9, 129.2, 127.1, 125.9, 121.7, 120.5, 88.4, 42.9.
3,3-Diallylhexahydroisobenzofuran-1(3H)-one (4b). Using the
standard acid anhydride double allylboration procedure and flash
chromatography on silica gel (15% EtOAc/hexanes) afforded 4.18
(0.110 g, 99%) as a clear oil. Rf = 0.50 (15% EtOAc/hexanes); IR (thin
film) νmax 3077, 2936, 2859, 1771, 1640, 1441, 1337, 1182, 1125, 976,
916 cm−1; 1H NMR (400 MHz, CDCl3): δ 5.86−5.71 (2H, m), 5.19−
5.10 (4H, m), 2.99 (1H, dd, J = 6.5, 6.5 Hz), 2.61−2.53 (2H, m),
2.37−2.31 (2H, m), 2.28−2.19 (2H, m), 1.81−1.72 (2H, m), 1.62−
1.52 (2H, m), 1.27−1.08 (4H, m); 13C NMR (100 MHz, CDCl3): δ
177.6, 132.5, 132.5, 119.6, 119.5, 86.9, 41.1, 39.8, 39.5, 37.5, 24.9, 23.9,
23.2, 22.8; LRMS (DART+) m/z (rel intensity) 238.2 (100) [M +
NH4]+, 221.2 (44) [M + H]+; HRMS (DART+) m/z calcd for
C14H21O2 [M + H]+: 221.1542. Found: 221.1545.
(3aR(S),4S(R),7R(S),7aS(R))-3,3-Diallyl-3a,4,7,7a-tetrahydro-4,7-
methanoisobenzofuran-1(3H)-one (4c). Using the standard acid
anhydride double allylboration procedure and flash chromatography
on silica gel (20% EtOAc/hexanes) afforded 4c (0.111 g, 96%) as a
clear oil. Rf = 0.53 (20% EtOAc/hexanes); IR (thin film) νmax 3076,
2982, 1750, 1641, 1336, 1328, 1205, 1145, 1016, 1000, 964, 920, 828
cm−1; 1H NMR (400 MHz, CDCl3): δ 6.24−6.19 (2H, m), 5.88 (1H,
dddd, J = 17.0, 10.5, 8.0, 6.0 Hz), 5.24 (1H, dddd, J = 17.5, 10.5, 7.5,
7.5 Hz), 5.22−5.13 (4H, m), 3.27−3.25 (1H, m), 3.05−3.03 (1H, m),
2.74−2.72 (1H, m), 2.63 (1H, dddd, J = 14.5, 6.0, 1.5, 1.5 Hz), 2.46−
2.39 (2H, m), 2.30 (1H, dddd, J = 14.0, 7.0, 1.0, 1.0 Hz), 2.20 (1H, d, J
= 8.0 Hz), 1.50−1.48 (2H, m); 13C NMR (100 MHz, CDCl3): δ
177.4, 139.1, 138.1, 132.7, 131.5, 121.0, 119.6, 86.7, 50.4, 49.5, 46.1,
45.4, 44.8, 44.0, 39.3; LRMS (DART+) m/z (rel intensity) 248.2 (93)
[M + NH4]+, 231.1 (100) [M + H]+; HRMS (DART+) m/z calcd for
C15H19O2 [M + H]+: 231.1385. Found: 231.1394.
4-Phenethylhepta-1,6-dien-4-amine (2m). Using the standard
nitrile double allylboration procedure and flash chromatography on
silica gel (15% MeOH/EtOAc + 0.5% NEt3) afforded 2m (0.053 g,
48%) as a yellow oil. Rf = 0.38 (15% MeOH/EtOAc); IR (thin film)
νmax 3360, 3187, 3074, 3026, 3002, 2927, 2860, 1638, 1603, 1496,
1456, 998, 915, 847, 824, 746, 699 cm−1; 1H NMR (400 MHz,
CDCl3): δ 7.30−7.25 (2H, m), 7.19−7.15 (3H, m), 5.92−5.82 (2H,
dddd, J = 16.0, 11.0, 7.5, 7.5 Hz), 5.17−5.12 (4H, m), 2.68−2.63 (2H,
m), 2.23−2.21 (4H, m), 1.90 (2H, br s), 1.69−1.65 (2H, m); 13C
NMR (100 MHz, CDCl3): δ 142.7, 133.8, 128.6, 128.5, 126.0, 119.0,
54.2, 44.6, 42.1, 30.2; LRMS (DART+) m/z (rel intensity) 216.2 (100)
[M + H]+; HRMS (DART+) m/z calcd for C15H22N [M + H]+:
216.1752. Found: 216.1759.
4-((1H-Indol-2-yl)methyl)hepta-1,6-dien-4-amine (2n). Using the
standard nitrile double allylboration procedure and flash chromatog-
raphy on silica gel (20% MeOH/EtOAc + 0.5% NEt3) afforded 2n
(0.078 g, 65%) as a light brown solid. Mp 78−80 °C (CDCl3); Rf =
0.33 (20% MeOH/EtOAc); IR (thin film in CDCl3) νmax 3409, 3334,
3164, 3063, 2976, 2919, 2849, 1640, 1576, 1458, 1439, 1365, 1340,
1234, 1109, 997, 915, 742 cm−1; 1H NMR (400 MHz, CDCl3): δ 8.31
(1H, br s), 7.63 (1H, d, J = 8.0 Hz), 2.20−2.02 (4H, m), 7.36 (1H, d, J
= 8.0 Hz), 7.18 (1H, ddd, J = 7.0, 7.0, 1.0 Hz), 7.13−7.10 (1H, m),
7.08 (1H, d, J = 2.0 Hz), 5.94 (2H, dddd, J = 17.5, 10.0, 7.5, 7.5 Hz),
5.17−5.08 (4H, m), 2.87 (2H, s), 2.29−2.24 (2H, m); 13C NMR (100
MHz, CDCl3): δ 136.2, 134.4, 128.9, 123.9, 122.1, 119.7, 119.6, 118.8,
111.6, 111.3, 54.9, 44.4, 35.8; LRMS (ESI+) m/z (rel intensity) 241.2
(24) [M + H]+, 224.1 (100), 130.1 (69); HRMS (ESI+) m/z calcd for
C16H21N2 [M + H]+: 241.1699. Found: 241.1695.
4-(Pyridin-4-yl)hepta-1,6-dien-4-amine (2o). Using the standard
nitrile double allylboration procedure and flash chromatography on
silica gel (10% MeOH/EtOAc) afforded 2o (0.085 g, 85%) as a yellow
oil. Rf = 0.30 (10% MeOH/EtOAc); IR (thin film) νmax 3366, 3287,
3076, 2978, 2925, 2855, 1691, 1641, 1597, 1553, 1441, 1410, 1070,
1
995, 919, 822, 566 cm−1; H NMR (400 MHz, CDCl3): δ 8.56−8.55
(2H, m), 7.36−7.35 (2H, m), 5.49 (2H, dddd, J = 17.0, 10.5, 8.5, 6.5
Hz), 5.10−5.06 (4H, m), 2.62 (2H, dddd, J = 14.0, 6.5, 1.5, 1.5 Hz),
2.44−2.38 (2H, m), 1.94 (2H, br s); 13C NMR (100 MHz, CDCl3): δ
156.1, 149.8, 132.9, 121.5, 119.8, 57.1, 47.7; LRMS (DART+) m/z (rel
intensity) 189.1 (100) [M + H]+; HRMS (DART+) m/z calcd for
C12H17N2 [M + H]+: 189.1392. Found: 189.1389.
(3aS(R),4S(R),7R(S),7aR(S))-3,3-Diallyl-3a,4,7,7a-tetrahydro-4,7-
methanoisobenzofuran-1(3H)-one (4d). Using the standard acid
anhydride double allylboration procedure and flash chromatography
on silica gel (30% EtOAc/hexanes) afforded 4d (0.117 g, 99%) as a
clear oil. Rf = 0.35 (20% EtOAc/hexanes); IR (thin film) νmax 3076,
2979, 2944, 2871, 1767, 1641, 1436, 1338, 1201, 1129, 998, 918, 812,
721 cm−1; 1H NMR (400 MHz, CDCl3): δ 6.29−6.23 (2H, m), 5.89−
5.71 (2H, m), 5.21−5.15 (4H, m), 3.39 (1H, dd, J = 9.0, 5.0 Hz),
3.25−3.22 (1H, m), 3.13−3.09 (1H, m), 2.80 (1H, dd, J = 9.0, 3.5
Hz), 2.54−2.49 (1H, m), 2.38−2.33 (3H, m), 1.64 (1H, ddd, J = 8.5,
2.0, 2.0 Hz), 1.43−1.41 (1H, m); 13C NMR (100 MHz, CDCl3): δ
177.6, 136.5, 134.8, 120.7, 119.4, 87.1, 53.1, 49.9, 45.9, 45.4, 45.1, 40.3;
LRMS (DART+) m/z (rel intensity) 248.2 (86) [M + NH4]+, 231.1
4-Benzylhepta-1,6-dien-4-amine (2p). Using the standard nitrile
double allylboration procedure and flash chromatography on silica gel
(EtOAc + 0.5% NEt3) afforded 2p (0.035 g, 35%) as a light yellow oil.
Rf = 0.20 (EtOAc); IR (thin film) νmax 3364, 3291, 3074, 3028, 3003,
2976, 2922, 2853, 1640, 1603, 1589, 1495, 1452, 1441, 1414, 1082,
1032, 997, 914, 745, 704 cm−1; 1H NMR (400 MHz, CDCl3): δ 7.32−
7.28 (2H, m), 7.25−7.21 (3H, m), 5.92 (2H, dddd, J = 17.5, 10.0, 7.5,
7.5 Hz), 5.18−5.09 (4H, m), 2.69 (1H, s), 2.18 (2H, dddd, J = 14.0,
7.5, 1.0, 1.0 Hz), 2.09 (2H, dddd, J = 14.0, 7.5, 1.0, 1.0 Hz), 1.47 (2H,
br s); 13C NMR (100 MHz, CDCl3): δ 137.8, 134.3, 130.9, 128.3,
1220
dx.doi.org/10.1021/jo302194n | J. Org. Chem. 2013, 78, 1216−1221