The Journal of Organic Chemistry
NOTE
concentrated under reduced pressure. The residue was purified by flash
chromatography (pentane:EtOAc, 10:1) to give 1h as a colorless oil in
61% yield (261 mg, 1.46 mmol). 90:10 er determined by HPLC analysis
(Chiralcel OD-J, 0.5% 2-propanol in hexanes, 0.5 mL/min, λ = 210 nm,
R isomer 46.2 min, S isomer 43.534 min); 1H NMR (500 MHz, CDCl3)
δ 9.73 (d, J = 1.5 Hz, 1H), 7.38ꢀ7.27 (m, 5H), 4.53 (s, 2H), 3.67 (ddd,
J = 14.7, 9.4, 6.0 Hz, 2H), 2.72ꢀ2.62 (m, 1H), 1.14 (d, J = 7.1 Hz, 3H).
Synthesis of Aldehydes 1i. 3-((tert-Butyldiphenylsilyl)oxy)-2,2-di-
methylpropan-1-ol (30).47 To a suspension of NaH (86 mg, 2.88 mmol) in
THF (12 mL) was added commercial available diol 29 (300 mg, 2.88
mmol) in small portions at rt. The resultant mixture was stirred for 1 h
before TBDPSCl (1 mL, 2.9 M in THF) was added dropwise during 1 h.
The reaction was stirred overnight and quenched by addition of H2O
(10 mL). The aqueous phase was extracted (Et2O, 3 ꢁ 10 mL), and the
combined organic phases were washed (H2O, 2 ꢁ 20 mL), dried (MgSO4),
and concentrated under reduced pressure. The residue was purified by flash
chromatography (pentane:EtOAc, 8:1) to give 30 as a colorless oil in 77%
yield (759 mg, 2.21 mmol). 1H NMR (500 MHz, CDCl3) δ 7.69ꢀ7.63
(m, 4H), 7.48ꢀ7.37 (m, 6H), 3.51 (d, J = 6.0 Hz, 2H), 3.48 (d, J = 4.8 Hz,
2H), 2.36 (t, J = 6.0 Hz, 1H), 1.06 (d, J = 2.9 Hz, 9H), 0.89 (s, 6H).
3-((tert-Butyldiphenylsilyl)oxy)-2,2-dimethylpropanal (1i).47 To a
solution of alcohol 30 (287 mg, 838 μmol) in CH2Cl2 (2 mL) was
added TEMPO (1.3 mg, 838 μmol) at rt. After 5 min, KBr (100 mg)
dissolved in aqueous NaHCO3 (5% w/w, 5.7 mL) was added. The
resultant mixture turned apricot and was cooled to 0 °C prior to
dropwise addition of sodium hypochlorite (10% active Clꢀ, 1.2 mL)
until the color of the solution stayed red. The mixture was then stirred
for an additional 1 h. The aqueous phase was extracted (CH2Cl2,
3 ꢁ 5 mL), andthecombinedorganicphaseswere washedwith NaHCO3
(satd aq, 10 mL) and brine (satd aq, 10 mL), dried (MgSO4), and
concentrated under reduced pressure. The residue was purified by flash
chromatography (pentane:EtOAc, 10:1) to give 1i as a colorless oil in
49% yield (139 mg, 407 μmol). 1H NMR (500 MHz, CDCl3) δ 9.60 (s,
1H), 7.66ꢀ7.59 (m, 4H), 7.45ꢀ7.36 (m, 6H), 3.64 (s, 2H), 1.06 (d, J =
5.2 Hz, 6H), 1.03 (s, 9H).
(20 mg, 130 μmol). Reaction time: 12 h. 1H NMR (500 MHz, CDCl3) δ
7.40ꢀ7.27 (m, 5H), 6.42ꢀ6.25 (m, 2H), 5.88ꢀ5.79 (m, 1H), 5.25ꢀ5.20
(m, 1H), 5.13ꢀ5.08 (m, 2H), 4.55 (d, J = 18.4 Hz, 2H), 4.08 (d, J = 6.0 Hz,
2H). 1H NMR analysis on the crude reaction mixture.
(E)-((Hexa-3,5-dien-1-yloxy)methyl)benzene (3e).50 Prepared accord-
ing to the general procedure using aldehyde 1e (40 mg, 240 μmol).
Reaction time: 3 h. 1H NMR (500 MHz, CDCl3) δ 7.39ꢀ7.27 (m, 7H),
6.32 (dt, J = 17.0, 10.3 Hz, 1H), 6.12 (dd, J = 15.3, 10.4 Hz, 1H),
5.77ꢀ5.69 (m, 1H), 5.11 (d, J = 17.0 Hz, 1H), 4.99 (d, J = 10.1 Hz, 1H),
4.52 (s, 2H), 3.53 (t, J = 6.8 Hz, 2H), 2.42 (q, J = 6.6 Hz, 2H) 1H NMR
analysis on the crude reaction mixture.
(E)-((Hepta-4,6-dien-2-yloxy)methyl)benzene (3f). Prepared accord-
ing to the general procedure using aldehyde 1f (20 mg, 110 μmol).
1
Reaction time: 12 h. Colorless oil. H NMR (500 MHz, CDCl3) δ
7.28ꢀ7.23 (m, 4H), 7.22ꢀ7.16 (m, 1H), 6.24 (dt, J = 17.0, 10.3 Hz, 1H),
6.02 (dd, J = 15.2, 10.4 Hz, 1H), 5.64 (dt, J = 15.0, 7.3 Hz, 1H), 5.03 (d,
J = 17.0 Hz, 1H), 4.91 (d, J = 10.1 Hz, 1H), 4.48 (d, J = 11.8 Hz, 1H), 4.42
(d, J = 11.8 Hz, 1H), 3.54ꢀ3.46 (m, 1H), 2.36ꢀ2.29 (m, 1H), 2.19 (dt,
J = 14.1, 6.9 Hz, 1H), 1.12 (d, J = 6.2 Hz, 3H); 13C NMR (126 MHz,
CDCl3) δ 138.9, 137.1, 133.2, 131.0, 128.3, 127.6, 127.4, 115.3, 74.6,
70.4, 39.6, 19.6; IR (film) νmax = 2970, 1092, 1005 cmꢀ1; HRMS(FAB+)
calcd for C14H19O (M + H): 203.1430, found: 203.1429.
(E)-N-(Hepta-4,6-dien-2-yl)-4-methylbenzenesulfonamide (3g).17
Prepared according to the general procedure using aldehyde 1g
(50 mg, 210 μmol). Reaction time: 12 h. 1H NMR (500 MHz, CDCl3)
δ 7.75 (t, J = 10.7 Hz, 2H), 7.30 (d, J = 8.0 Hz, 2H), 6.17 (dt, J = 17.0,
10.3 Hz, 1H), 5.97 (dd, J = 15.2, 10.4 Hz, 1H), 5.38 (dt, J = 15.1, 7.5 Hz,
1H), 5.10 (d, J = 17.0 Hz, 1H), 5.02 (d, J = 10.2 Hz, 1H), 4.37 (d, J =
7.4 Hz, 1H), 3.42ꢀ3.31 (m, 1H), 2.43 (s, 3H), 2.14 (t, J = 6.8 Hz, 2H),
1.09 (d, J = 6.6 Hz, 3H).
(S,E)-(((2-Methylhexa-3,5-dien-1-yl)oxy)methyl)benzene (3h). Pre-
pared according to the general procedure using aldehyde 1h (46 mg, 260
μmol). Reaction time: 12 h. Colorless oil. 88:12 er determined by HPLC
analysis (Chiralcel OD-J, 1% 2-propanol in hexanes, 0.5 mL/min, λ =
210 nm, R isomer 14.9 min, S isomer 16.6 min); 1H NMR (500 MHz,
CDCl3) δ 7.30ꢀ7.24 (m, 4H), 7.24ꢀ7.18 (m, 1H), 6.24 (dt, J = 16.9,
10.2 Hz, 1H), 6.03 (dd, J = 15.3, 10.4 Hz, 1H), 5.61 (dd, J = 15.4, 7.2 Hz,
1H), 5.05 (dd, J = 17.0, 1.2 Hz, 1H), 4.92 (dd, J = 10.1, 1.1 Hz, 1H), 4.44
(s, 2H), 3.31 (dd, J = 9.1, 6.5 Hz, 1H), 3.24 (dd, J = 9.1, 6.8 Hz, 1H), 2.48
(hept, J = 6.7 Hz, 1H), 0.99 (d, J = 6.8 Hz, 3H); 13C NMR (126 MHz,
CDCl3) δ 138.5, 137.4, 137.3, 130.5, 128.3, 127.6, 127.5, 115.4, 75.0,
73.0, 36.8, 16.9; IR (film) νmax = 2856, 1095, 1004 cmꢀ1; HRMS
(FAB+) calcd for C14H19O (M + H): 203.1430, found: 203.1428.
(E)-1-(Buta-1,3-dien-1-yl)-4-nitrobenzene (3j). Prepared according
to the general procedure in darkness using commercially available
aldehyde 1j (50 mg, 330 μmol). Reaction time: 12 h. White solid, mp:
77.6ꢀ78.2 °C. 1H NMR (500 MHz, CDCl3) δ 8.21ꢀ8.14 (m, 2H), 7.52
(t, J = 5.6 Hz, 2H), 6.92 (dd, J = 15.7, 10.5 Hz, 1H), 6.60 (d, J = 15.7 Hz,
1H), 6.53 (dt, J = 16.9, 10.3 Hz, 1H), 5.47 (d, J = 16.9 Hz, 1H), 5.34 (d,
J = 10.0 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 146.8, 143.6, 136.4,
134.0, 130.4, 126.8, 124.0, 120.9; IR (film) νmax = 1516, 1344,
1003 cmꢀ1; HRMS (FAB+) calcd for C10H10O2N (M + H):
176.0706, found: 176.0706.
General Procedures for Diene Formation. To a solution of
(E)-1,3-bis(trimethylsilyl)prop-1-ene 2b (2 equiv), BF3 OEt2 (2 equiv),
3
and 4 Å molecular sieves (100 mg/mL solvent) in CH2Cl2 (1 mL/150
μmol aldehyde) at ꢀ78 °C was added a 0.01 M solution of 1bꢀj
(1 equiv) and 1-methylnaphthalene (1 equiv) in CH2Cl2 dropwise over
1 h. The mixture was stirred for an additional 2ꢀ18 h. The reaction was
monitored by TLC and quenched by addition of NH4Cl (satd aq,
1.5 mL/150 μmol aldehyde). The aqueous phase was extracted
(CH2Cl2, 2 ꢁ 2 mL/150 μmol aldehyde), dried (MgSO4), and
concentrated under reduced pressure to give the product.
(E)-tert-Butyl(octa-5,7-dien-1-yloxy)diphenylsilane (3b).48 Prepared
according to the general procedure using aldehyde 1b (43 mg, 126
μmol). Reaction time: 2 h. Colorless oil. 1H NMR (500 MHz, CDCl3) δ
7.66 (d, J = 6.6 Hz, 4H), 7.40 (dq, J = 14.1, 7.1 Hz, 6H), 6.30 (dt, J = 17.2,
10.3 Hz, 1H), 6.03 (dd, J = 15.6, 10.3 Hz, 1H), 5.72ꢀ5.64 (m, 1H), 5.08
(d, J = 16.7 Hz, 1H), 4.95 (d, J = 10.6 Hz, 1H), 3.66 (t, J = 6.3 Hz, 2H),
2.07 (dd, J = 14.5, 7.2 Hz, 1H), 1.63ꢀ1.43 (m, 2H), 1.05 (s, 9H).
(E)-((Hepta-4,6-dien-1-yloxy)methyl)benzene (3c). Prepared ac-
cording to the general procedure using aldehyde 1c (100 mg, 560
μmol). Reaction time: 12 h. Colorless oil. 1H NMR (500 MHz, CDCl3)
δ 7.30ꢀ7.23 (m, 4H), 7.23ꢀ7.18 (m, 1H), 6.23 (dt, J = 17.0, 10.3 Hz,
1H), 5.98 (dd, J = 15.2, 10.4 Hz, 1H), 5.67ꢀ5.58 (m, 1H), 5.01 (d, J =
16.8 Hz, 1H), 4.89 (d, J = 10.2 Hz, 1H), 4.42 (s, 2H), 3.40 (t, J = 6.5 Hz,
2H), 2.11 (q, J = 7.2 Hz, 2H), 1.69ꢀ1.60 (m, 2H); 13C NMR (126 MHz,
CDCl3) δ 138.6, 137.2, 134.5, 131.3, 128.3, 127.6, 127.5, 114.9, 72.9,
Synthesis and Spectral Data of Homolylic Alcohol
6. 7-(Benzyloxy)hept-1-en-4-ol (6). To (E)-1,3-bis(trimethylsilyl)prop-
1-ene (105 mg, 561 μmol), allyltrimethylsilane (64 mg, 561 μmol), and
BF3 OEt2 (138 μL, 1.12 mmol) in CH2Cl2 (1 mL) in the precense of 4 Å
3
Ms (50 mg) were added aldehyde 1c (50 mg, 281 μmol) and 1-methyl-
naphthalene (78 μL, 281 μmol) dissolved in CH2Cl2 (1 mL) dropwise
(1 mL/h) at ꢀ40 °C. The reaction was monitored by TLC and quenched
by addition of NH4Cl (satd aq, 2 mL). The aqueous phase was extracted
(CH2Cl2, 2 ꢁ 2 mL), dried (MgSO4), and concentrated under reduced
69.6, 29.2, 29.1; IR (film) νmax = 2937, 2854, 1454, 1105, 1004 cmꢀ1
;
HRMS(FAB+) calcd for C14H19O (M + H): 203.1430, found: 203.1432.
(E)-((Penta-2,4-dien-1-yloxy)methyl)benzene (3d).49 Prepared accord-
ing to the general procedure using commercially available aldehyde 1d
1
pressure to give 6 as a colorless oil in 80% yield. H NMR (500 MHz,
CDCl3) δ 7.30ꢀ7.23 (m, 4H), 7.21 (ddd, J = 11.9, 5.8, 2.7 Hz, 1H),
8074
dx.doi.org/10.1021/jo2013466 |J. Org. Chem. 2011, 76, 8070–8075