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LETTER
(6) For a review see: (a) Robertson, J.; Pillai, J.; Lush, R. K.
Chem. Soc. Rev. 2001, 30, 94. For typical examples see:
(b) Storey, J. M. D. Tetrahedron Lett. 2000, 41, 8173.
(c) Curran, D. P.; Shen, W. J. Am. Chem. Soc. 1993, 115,
6051. (d) Beaulieu, F.; Arora, J.; Veith, U.; Taylor, N. J.;
Chapell, B. J.; Snieckus, V. J. Am. Chem. Soc. 1996, 118,
8727. (e) Curran, D. P.; Xu, J. J. Am. Chem. Soc. 1996, 118,
3142. (f) Curran, D. P.; Yu, H.; Liu, H. Tetrahedron 1994,
50, 7343. (g) Curran, D. P.; Liu, H. T. J. Chem. Soc., Perkin
Trans. 1 1994, 1377. (h) Curran, D. P.; Kim, D.; Liu, H.;
Shen, W. J. Am. Chem. Soc. 1988, 110, 5900. (i) Beaufils,
F.; Dénès, F.; Renaud, P. Org. Lett. 2004, 6, 2563.
Hz), 4.79 (br s, 1 H, D2O exchangeable), 6.89 (d, 2 H, J = 9.0
Hz), 7.53 (d, 2 H, J = 9.0 Hz); 13C NMR (75 MHz, CDCl3):
d = 14.22, 26.10, 35.32, 37.67, 47.47, 52.97, 55.44, 71.07,
114.02, 121.26, 132.95, 156.49, 176.39; MS (ESI): m/z =
261.1 [M + H+]; Anal. Calcd for C15H20N2O2: C, 69.20; H,
7.74; N, 10.76. Found: C, 68.02; H, 7.65; N, 10.83.
Compound 13f: 66%; light yellowish solid; mp 82.4–83.6
°C. 1H NMR (300 MHz, CDCl3): d = 1.15 (d, 3 H, J = 7.2
Hz), 1.59–1.69 (m, 1 H), 1.76–1.86 (m, 1 H), 1.91–2.03 (m,
2 H), 2.31–2.39 (m, 1 H), 2.97–3.04 (m, 1 H), 3.23–3.30 (m,
2 H), 3.68–3.73 (m, 1 H, J = 7.5 Hz, J = 9.6 Hz), 3.80 (s, 3
H), 4.78 (br s, 1 H, D2O exchangeable), 6.90 (d, 2 H, J = 9.0
Hz), 7.53 (d, 2 H, J = 9.0 Hz); 13C NMR (75 MHz, CDCl3):
d = 11.89, 26.26, 28.78, 39.34, 47.62, 52.08, 55.44, 70.64,
114.02, 121.09, 132.80, 156.47, 177.70; MS (ESI): m/z =
261.1 [M + H+]; Anal. Calcd for C15H20N2O2: C, 69.20; H,
7.74; N, 10.76. Found: C, 68.97; H, 7.62; N, 10.51.
(7) (a) Sato, T.; Yamazaki, T.; Nakanishi, Y.; Uenishi, J.; Ikeda,
M. J. Chem. Soc., Perkin Trans. 1 2002, 1438. (b) Takasu,
K.; Ohsato, H.; Ihara, M. Org. Lett. 2003, 5, 3017.
(c) Hilton, S. T.; Ho, T. C. T.; Pljevaljcic, G.; Schulte, M.;
Jones, K. Chem. Commun. 2001, 209.
(8) Genenal procedure: To a stirred solution of 5 (2 mmol) in
degassed toluene (50 mL), Bu3SnH (0.688 mL, 2.4 mmol)
and AIBN (33 mg, 0.2 mmol) in toluene (20 mL) were added
dropwise over 7 h using a syringe pump under reflux. After
addition, the solution was heated at reflux for a further 2 h.
The solvent was removed, and the residue was purified by
flash chromatography on silica gel (petroleum ether–
EtOAc, 5:1–1:1) to give products 12, 13, and 14 (order of
elution).
Compound 14f: 8%; light yellowish oil. 1H NMR (300 MHz,
CDCl3): d = 1.35 (d, 3 H, J = 6.9), 1.78–1.89 (m, 2 H), 2.17–
2.25 (m, 1 H), 2.88–2.91 (m, 1 H), 3.20–3.25 (m, 1 H), 3.44–
3.58 (m, 2 H), 3.64–3.70 (m, 1 H), 3.80 (s, 3 H), 3.91–3.93
(m, 1 H), 4.18–4.32 (m, 1 H), 4.76 (br s, 1 H, D2O
exchangeable), 6.73 (d, 2 H), 8.10 (m, 1 H); MS (ESI):
m/z = 261.1 [M + H+].
(9) To a solution of 13b (180 mg, 0.5 mmol) in EtOAc (4 mL)
at r.t. was added a saturated solution of HCl in EtOAc (5
mL). After stirring for 2 h, the reaction was quenched with
30 % aq NaOH, and extracted with EtOAc (3 × 15 mL).The
organic layer was washed with brine (2 × 10 mL), dried over
MgSO4, and concentrated in vacuo to give 13f (113 mg,
87%) as a light yellowish solid (mp 82.1–84.0 °C).
Compound 12f: 7%; light yellowish oil. 1H NMR (300 MHz,
CDCl3): d = 1.10 (d, 3 H, J = 7.2 Hz, 1.79–1.89 (m, 2 H),
1.92–2.04 (m, 2 H), 2.21–2.26 (m, 1 H), 2.87–2.95 (m, 1 H),
3.22–3.30 (m, 1 H), 3.34–3.38 (dd, 1 H, J = 3.6 Hz, J = 9.6
Hz), 3.80 (s, 3 H), 3.81–3.86 (dd, 1 H, J = 6.3 Hz, J = 9.8
Synlett 2005, No. 12, 1865–1868 © Thieme Stuttgart · New York