1
704
Synlett
N. Griebenow et al.
Letter
Supporting Information
mmol, 1.33 mL) at –78 °C. The solution was stirred at –78 °C for
1
h followed by the dropwise addition of 12 (210 mg, 0.55
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0034-1380740.
mmol) dissolved in anhydrous THF (3 mL). The mixture was
stirred at 78 °C for 1 h and at –70 °C for 3 d. The mixture was
S
u
p
p
ortioIgnfrm oaitn
S
u
p
p
ortioIgnfrm oaitn
quenched with sat. aq NaHCO3 (5 mL). H O (2 mL) was added
2
and the mixture was extracted with Et O (3 ×). The combined
2
References and Notes
organic phases were washed with brine and sat. aq NaHCO3.
Subsequently, the organic phase was dried and concentrated.
(1) Reetz, M. T.; Griebenow, N.; Goddard, R. J. Chem. Soc., Chem.
1
13
The crude product was analyzed by H and C NMR spectros-
copy. The spectra showed only signals of 12 and 13. The corre-
sponding stereoisomer of 13 was not observed. Finally, the
Commun. 1995, 1605.
(2) Chilton, W. S.; Tsou, G.; Kirk, L.; Benedict, R. G. Tetrahedron Lett.
1968, 6283.
residue was purified on silica gel (Et O–pentane, 1:4 v/v). Yield:
2
(
(
3) Casara, P.; Jund, K.; Bey, P. Tetrahedron Lett. 1984, 25, 1891.
4) Hiemstra, H.; Fortgens, H. P.; Speckamp, W. N. Tetrahedron Lett.
2
1 mg (0.05 mmol, 14% based on recovered starting material).
1
H NMR (200 MHz, CDCl ): δ = 0.91 [d, J = 6.8 Hz, 3 H, CH -
3
2
1
984, 25, 3115.
5) Marshall, J. A.; Robinson, E. D.; Zapata, A. J. Org. Chem. 1989, 54,
854.
CH(CH ) ], 0.93 [d, J = 6.8 Hz, 3 H, CH -CH(CH ) ], 1.30–1.49 [m,
3
2
2
3 2
(
2
H, CH -CH(CH ) ], 1.44 [br s, 9 H, C(CH ) ], 1.48 [s, 9 H,
2 3 2 3 3
5
C(CH ) ], 1.59–1.67 [m, 1 H, CH CH(CH ) ], 1.71 and 1.72 [2 s,
3
3
2
3 2
(
(
(
6) Chung, J. Y. L.; Wasicak, J. T. Tetrahedron Lett. 1990, 31, 3957.
7) Corey, E. J.; Fuchs, P. L. Tetrahedron Lett. 1972, 3769.
8) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc., Trans.
6
1
1
2
1
H, C=C=C(CH ) ], 3.54 (d, J = 7.6 Hz, 1 H, CHOH), 4.27–4.33 (m,
3 2
H, NHCH), 4.42 (d, J = 9.6 Hz, 1 H, NHCH), 4.46 (d, J = 7.6 Hz,
13
H, CHOH). C NMR (50 MHz, CDCl ): δ = 20.04, 20.36, 22.36,
3
1
915, 107, 1080.
9) Allinger, N. L.; Zalkow, V. J. Org. Chem. 1960, 25, 701.
of tert-Butyl (2R,4S)-4-[(tert-Butoxycar-
bonyl)amino]-2-hydroxy-6-methyl-3-(2-methylprop-1-en-
-ylidene)heptanoate (13): Under an atmosphere of argon,
2.83, 24.99, 28.09, 28.41, 43.97, 48.17, 71.12, 79.36, 81.99,
01.20, 104.57, 155.40, 172.58, 199.06. MS (EI): m/z (%) = 29
(
(
10) Synthesis
(17.25), 41 (27.93), 57 (100.00), 86 (59.50), 124 (11.85), 130
(
=
9
42.03), 136 (12.08), 226 (10.12), 253 (22.69); MS (CI, NH ): m/z
3
1
+
384 [M + H] . Anal. Calcd for C21H37NO (384.53): C, 65.77; H,
5
i-Pr NH (230 mg, 2.27 mmol) was dissolved in anhydrous
2
.72; N, 3.65. Found: C, 65.80; H, 9.66; N, 3.66.
THF (2 mL) and charged with n-BuLi (1.6 M in n-hexane, 2.16
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Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 1702–1704