8614
Q. Chai et al. / Tetrahedron Letters 47 (2006) 8611–8615
the product was purified by flash chromatography on
3.34–3.43 (m, 1H), 4.16 (t, 1H, J = 7.4 Hz), 4.32 (t, 1H,
J = 8.6 Hz), 4.65 (m, 1H), 6.16 (m, 1H), 6.22 (dd, 1H),
6.68 (d, 1H, J = 7.8), 6.87 (m, 1H), 6.97 (d, 1H, J = 7.8),
7.10–7.32 (m, 6H); 13C NMR (CDCl3) d 32.3, 35.6, 35.7,
39.1, 41.6, 67.6, 71.3, 117.5, 117.6, 123.4, 123.6, 127.3,
127.7, 128.5, 129.7, 130.2, 133.6, 137.5, 138.0, 141.6, 167.1;
MS (M+): 385.5; Calcd for C25H24N2O2: C: 78.10, H:
6.29, N: 7.29, O: 8.32. Found: C: 77.89, H: 6.07, N: 6.85,
O: 8.87; [a]D ꢀ79.2 (c 0.095, CHCl3).
silica gel (methanol/CH2Cl2: from 2% to 10%). Data for
the product compounds 3 was obtained:
1
Rp,S-3-(R = t-Bu): Yield: 53%; H NMR (CDCl3) d 0.96
(s, 9H), 2.91–3.13 (m, 3H), 3.15–3.31 (m, 4H), 3.37–3.45
(m, 1H), 4.07 (dd, 1H, J = 7.6, J = 10.1), 4.25 (t, 1H), 4.35
(dd, 1H, J = 7.6, J = 10.1), 6.40 (m, 1H), 6.42 (m, 1H),
6.63 (d, 1H, J = 7.6), 6.72 (m, 1H), 6.86 (d, 1H, J = 7.6),
6.93 (m, 1H); 13C NMR (CDCl3) d 25.6, 33.7, 34.7, 34.9,
37.5, 68.3, 76.1, 116.3, 116.5, 123.6, 125.7, 127.5, 128.5,
129.8, 130.8, 131.0, 132.3, 133.7, 134.2, 137.5, 138.1, 162.9;
MS (M+): 335.5; [a]D ꢀ126.8 (c 0.085, MeOH).
1
Compound 5a: Yield: 55%; H NMR (CDCl3) d 0.95 (d,
9H), 2.87–3.10 (m, 4H), 3.13–3.33 (m, 3H), 3.36–3.41 (m,
1H), 4.05 (m, 1H), 4.29 (m, 1H), 4.37 (m, 1H), 6.17 (m,
1H), 6.25 (m, 1H), 6.67 (d, 1H, J = 7.6), 6.73 (m, 1H), 6.96
(d, 1H, J = 7.6), 7.05 (m, 1H); 13C NMR (CDCl3) d 25.3,
37.0, 37.2, 38.3, 39.2, 68.7, 76.5, 116.2, 116.9, 123.3, 125.3,
127.2, 128.8, 129.7, 130.1, 131.8,132.2, 133.6, 134.2, 137.3,
138.6, 141.2, 165.1; MS (M+): 351.5; Calcd for
C22H26N2O2: C: 75.40, H: 7.48, N: 7.99, O: 9.13. Found:
C: 75.21, H: 7.23, N: 7.72, O: 9.87; [a]D +66.5 (c 0.08,
CHCl3).
Rp,S-3-(R = benzyl): Yield: 42%; 1H NMR (CDCl3) d 2.76
(d, 1H, J = 9.2 Hz), 2.90–3.07 (m, 3H), 3.13–3.26 (m, 5H),
3.37–3.45 (m, 1H), 4.16 (t, 1H, J = 7.4 Hz), 4.31 (t, 1H,
J = 8.6 Hz), 4.61 (m, 1H), 6.38 (m, 1H), 6.43 (dd, 1H),
6.60 (d, 1H, J = 7.8), 6.78 (m, 1H), 6.85 (d, 1H, J = 7.8),
6.90 (m, 1H), 7.12–7.33 (m, 5H); 13C NMR (CDCl3) d
32.5, 34.2, 34.7, 37.7, 41.5, 67.9, 71.2, 116.4, 116.6, 123.7,
123.8, 126.3, 127.5, 128.4, 129.1, 130.9, 132.6, 137.6, 138.2,
139.3, 162.4; MS (M+): 369.5; [a]D ꢀ153.7 (c 0.095,
CHCl3).
1
Compound 5b: Yield: 72%; H NMR (CDCl3) d 2.77 (d,
1H, J = 9.2 Hz), 2.92–3.07 (m, 3H), 3.13–3.27 (m, 5H),
3.34–3.43 (m, 1H), 4.16 (t, 1H, J = 7.4 Hz), 4.32 (t, 1H,
J = 8.6 Hz), 4.65 (m, 1H), 6.16 (m, 1H), 6.22 (dd, 1H),
6.68 (d, 1H, J = 7.8), 6.87 (m, 1H), 6.97 (d, 1H, J = 7.8),
7.10–7.32 (m, 6H); 13C NMR (CDCl3) d 32.3, 35.6, 35.7,
39.1, 41.6, 67.6, 71.3, 117.5, 117.6, 123.4, 123.6, 127.3,
127.7, 128.5, 129.7, 130.2, 133.6, 137.5, 138.0, 141.6, 167.1;
MS (M+): 385.5; Calcd for C25H24N2O2: C: 78.10, H:
6.29, N: 7.29, O: 8.32. Found: C: 77.89, H: 6.07, N: 6.85,
O: 8.87; [a]D +80.2 (c 0.095, CHCl3).
1
Rp,R-3-(R = t-Bu): Yield: 48%; H NMR (CDCl3) d 0.96
(s, 9H), 2.91–3.13 (m, 3H), 3.15–3.31 (m, 4H), 3.37–3.45
(m, 1H), 4.07 (dd, 1H, J = 7.6, J = 10.1), 4.25 (t, 1H), 4.35
(dd, 1H, J = 7.6, J = 10.1), 6.40 (m, 1H), 6.42 (m, 1H),
6.63 (d, 1H, J = 7.6), 6.72 (m, 1H), 6.86 (d, 1H, J = 7.6),
6.93 (m, 1H); 13C NMR (CDCl3) d 25.6, 33.7, 34.7, 34.9,
37.5, 68.3, 76.1, 116.3, 116.5,123.6, 125.7, 127.5, 128.5,
129.8, 130.8, 131.0, 132.3, 133.7, 134.2, 137.5, 138.1, 162.9;
MS (M+): 335.5; [a]D +125.7 (c 0.082, MeOH).
Rp,R-3-(R = benzyl): Yield: 47%; 1H NMR (CDCl3) d
2.76 (d, 1H, J = 9.2 Hz), 2.90–3.07 (m, 3H), 3.13–3.26 (m,
5H), 3.37–3.45 (m, 1H), 4.16 (t, 1H, J = 7.4 Hz), 4.31 (t,
1H, J = 8.6 Hz), 4.61 (m, 1H), 6.38 (m, 1H), 6.43 (dd, 1H),
6.60 (d, 1H, J = 7.8), 6.78 (m, 1H), 6.85 (d, 1H, J = 7.8),
6.90 (m, 1H), 7.12–7.33 (m, 5H); 13C NMR (CDCl3) d
32.5, 34.2, 34.7, 37.7, 41.5, 67.9, 71.2, 116.4, 116.6, 123.7,
123.8, 126.3, 127.5, 128.4, 129.1, 130.9, 132.6, 137.6, 138.2,
139.3, 162.4; MS (M+): 369.5; [a]D +134.5 (c 0.010,
CHCl3).
17. General allylation procedure: An oven-dried flask was
charged with allytrichlorosilane (0.080 mL, 0.47 mmol),
ligand (0.006 mmol), diisopropylethylamine (0.35 mL,
2.0 mmol), and aldehyde (0.40 mmol) with CH3CN
(2.0 mL) under nitrogen at ꢀ40 ꢁC. The mixture was
stirred at this temperature and followed by TLC. After the
start material was consumed (6 h), the reaction was
quenched with aqueous saturated NaHCO3 (5.0 mL)
and the aqueous layer was extracted with ethyl acetate
(3 · 5 mL). The organic layers were combined, washed
with brine, and dried over anhydrous magnesium sulfate.
The solvent was removed and purification by flash
chromatography on silica gel (petroleum ether/ethyl
acetate, 95:5) furnished the known products with isolated
yields indicated that were characterized by the data
shown:
16. General preparation of oxazoline-aza-PCP-N-oxides 4, 5:
m-Chloroperoxybenzoic acid (70%, 122 mg, 0.50 mmol) in
CH2Cl2 (5 mL) was added dropwise to a solution of 3
(0.50 mmol) in CH2Cl2 (8 mL) under N2 at ꢀ10 ꢁC. The
reaction mixture was stirred at this temperature for
75 min, and water (10 mL) was added and extracted with
CHCl3 (10 · 3 mL). The combined organic layer was
washed with NaHCO3 (satd), brine, and dried over
anhydrous sodium sulfate. The solvent was removed and
purified by flash chromatography on silica gel (methanol/
CH2Cl2: from 5% to 20%) to produce products 4 and 5.
Purity was checked by Chiral HPLC (chiral OD-H,
hexane/iPrOH, 95:5) and found to be above 99% ee. Data
for the product compounds 4, 5 was obtained:
(S)-40-Methoxy-a-(2-propenyl) benzenemethanol: 1H
NMR (CDCl3) d 2.07–12 (broad, 1H), 2.48–2.55 (m,
2H), 3.80 (s, 3H), 4.76–4.79 (m, 1H), 5.09–5.19 (m, 2H),
5.79–5.88 (m, 1H), 6.90 (d, 2H, J = 8.6), 7.29 (d, 2H,
J = 8.6); 13C NMR (CDCl3) d 43.7, 56.1, 73.2, 113.7,
118.2, 127.1, 134.6, 135.9, 159.0; HRMS: 178.21; chiral
HPLC (OD-H, hexane/i-PrOH, 19:1, 0.2 mL/min): tR:
11.2 min, tS: 12.7 min; [a]D ꢀ48.1 (CHCl3, 1.0).
1
1
Compound 4a: Yield: 59%; H NMR (CDCl3) d 0.95 (d,
(S)-40-Chloro-a-(2-propenyl) benzenemethanol: H NMR
9H), 2.87–3.10 (m, 4H), 3.13–3.33 (m, 3H), 3.36–3.41 (m,
1H), 4.05 (m, 1H), 4.29 (m, 1H), 4.37 (m, 1H), 6.17 (m,
1H), 6.25 (m, 1H), 6.67 (d, 1H, J = 7.6), 6.73 (m, 1H), 6.96
(d, 1H, J = 7.6), 7.05 (m, 1H); 13C NMR (CDCl3) d 25.3,
37.0, 37.2, 38.3, 39.2, 68.7, 76.5, 116.2, 116.9, 123.3, 125.3,
127.2, 128.8, 129.7, 130.1, 131.8, 132.2, 133.6, 134.2, 137.3,
138.6, 141.2, 165.1; MS (M+): 351.5; Calcd for
C22H26N2O2: C: 75.40, H: 7.48, N: 7.99, O: 9.13. Found:
C: 75.21, H: 7.23, N: 7.72, O: 9.87; [a]D ꢀ67.8 (c 0.08,
CHCl3).
(CDCl3) d 1.61 (broad, 1H), 2.40–2.53 (m, 2H), 4.67–4.71
(m, 1H), 5.12–5.17 (m, 2H), 5.73–5.84 (m, 1H), 7.27–7.32
(m, 4H); 13C NMR (CDCl3) d 43.6, 46.7, 72.5, 118.7,
119.5, 126.9, 127.2, 128.2,128.5, 129.3, 132.9, 133.1, 133.9,
142.3; HRMS: 182.63; chiral HPLC (OD-H, hexane/i-
PrOH, 19:1, 0.2 mL/min): tR: 13.7 min, tS: 15.1 min; [a]D
ꢀ60.7 (c 1.5, CHCl3).
(S)-a-(2-Propenyl)-2-naphthalenemethanol: 1H NMR
(CDCl3) d 1.83–1.93 (broad, 1H), 2.47–2.56 (m, 2H),
4.83 (m, 1H), 5.11–5.19 (m, 2H), 5.63–5.82 (m, 1H), 7.41–
7.57 (m, 3H), 7.72–7.77 (m, 4H); 13C NMR (CDCl3) d
42.8, 69.8, 118.2, 122.9, 121.1, 127.8, 128.2,128.6, 131.6,
1
Compound 4b: Yield: 67%; H NMR (CDCl3) d 2.77 (d,
1H, J = 9.2 Hz), 2.92–3.07 (m, 3H), 3.13–3.27 (m, 5H),