ꢀ ꢀ
A. Chevalley, J.-P. Ferezou / Tetrahedron 68 (2012) 5882e5889
5889
ketone 38 (67%). 1H NMR (CDCl3, 360 MHz):
d
¼4.72, 4.65 (2 br s,
Supplementary data
4H), 2.58 (t, 4H, J¼7.3 Hz), 2.27 (t, 4H), 1.72 (s, 6H). 13C NMR (CDCl3,
90 MHz):
22.6 (CH3). IR:
d
¼209.7 (C), 144.5 (C), 110.1 (CH2), 40.9 (CH2), 31.4 (CH2),
1H and 13C NMR spectra for all compounds. Supplementary data
associated with this article can be found, in the online version, at
n
¼3422, 2966, 2928, 2857, 1715, 1648, 1447, 1375,
1120. HRMS (DI, EI) calcd for [C11H18NaO] m/z 189.1255, found
189.1262.
References and notes
4.20. (E)-6-Methyl-8-(tetrahydro-2H-pyran-2-yloxy)oct-6-en-
3-one (39)
ꢀ ꢀ
1. Demont, E.; Lopez, R.; Ferezou, J.-P. Synlett 1998, 1223e1226; Poupon, J. C.;
ꢀ ꢀ
Lopez, R.; Prunet, J.; Ferezou, J. P. J. Org. Chem. 2002, 67, 2118e2124; Lopez, R.;
ꢀ ꢀ
Poupon, J. C.; Prunet, J.; Ferezou, J. P.; Ricard, L. Synthesis 2005, 644e660.
ꢀ ꢀ
2. Poupon, J. C.; Demont, E.; Prunet, J.; Ferezou, J. P. J. Org. Chem. 2003, 68,
4700e4707.
To 1.05 mL of diisopropylamine (7.6 mmol, 3.0 equiv) in 5 mL of
dry THF at ꢁ78 ꢀC was added 3.6 mL of BuLi (2.1 M in hexanes,
7.5 mmol, 7.5 equiv) and stirred for 2 min. The reaction mixture was
warmed to 0 ꢀC and stirred for 10 min followed by addition of
3. Archibald, S. C.; Fleming, I. J. Chem. Soc., Perkin Trans. 1 1993, 751e754.
4. Intermediate formation of an imine of type 13, which is subsequently de-
protonated by an excess of base to furnish the acylating azaallylic anion of type
14 was demonstrated through the separate preparation of imines and their
acylation after deprotonation with BuLi to give the same enaminones as the
one-pot process described here. Starting from imine 13, R1¼R2¼R3¼Me, the
corresponding enaminone 25 was obtained in 58% yield, here again as a single
Z-isomer.
5. (a) Wittig, G.; Schmidt, H.-J.; Renner, H. Chem. Ber. 1962, 95, 2377e2383; (b) The
mechanism of this reaction has been largely debated, see, for example: New-
comb, M.; Burchill, M. T. J. Am. Chem. Soc. 1984, 106, 8276e8282.
6. (a) Majewski, M. Tetrahedron Lett. 1988, 29, 4057e4060; (b) Kowalski, C.; Creary,
X.; Rollin, A. J.; Burke, M. C. J. Org. Chem. 1978, 43, 2601e2608.
7. Majewski, M.; Gleave, D. M. J. Organomet. Chem. 1994, 470, 1e16.
8. Wittig, G.; Reif, H. Angew. Chem., Int. Ed. Engl. 1968, 7, 7e14.
commercial pivaldehyde (274 mL, 2.5 mmol 2.5 equiv). The resulting
colourless solution was stirred for 10 min at 0 ꢀC before adding
bromide 32 (4:1 E/Z mixture, 250.0 mg, 1.01 mmol, 1 equiv) diluted
in 1 mL of dry THF going from colourless to yellow then to red
solution. After 5 min at 0 ꢀC, commercial methyl iodide (630.0
mL,
10.1 mmol, 10.0 equiv) was added to the reddish reaction mixture,
which was stirred for 10 min at 0 ꢀC then warmed to room tem-
perature. This resulting pale yellow reaction mixture was stirred for
2 h and aq satd NH4Cl was added. Extraction with AcOEt followed
by purification by flash chromatography (Et2O/pentane 10:90 to
50:50) gave 151 mg of compound 39 (63%, E/Z 4:1). 1H NMR (CDCl3,
9. For another example of condensation (with a-chloro ketones): De Kimpe, N.;
Palamareva, M.; Schamp, N. J. Org. Chem. 1985, 50, 2993e2995.
10. For a recent introduction on one-pot processes, see: Climent, M. J.; Corma, A.;
Iborra, S. Chem. Rev. 2011, 111, 1072e1133.
300 MHz, signals for the major E-isomer):
d
¼5.33 (tq, J¼1.2, 6.3 Hz,
11. Zhuo, J.-C. Magn. Reson. Chem. 1996, 34, 21e29.
1H), 4.59 (t, J¼4.2 Hz, 1H), 4.20 (dd, J¼6.4, 12.0 Hz, 1H), 4.00 (dd,
J¼7.4, 12.0 Hz, 1H), 3.88 (m, 1H), 3.49 (m, 1H), 2.56e2.26 (m, 6H),
1.66 (s, 3H), 1.83e1.48 (m, 6H), 1.04 (t, J¼7.3 Hz, 3H). 1H NMR (C6D6,
12. Some recent oxidizing methods to prepare imines or enamines from amines.
(benzylic amines): (a) Gold catalyst/O2: Aschwanden, L.; Mallat, T.; Krumeich,
F.; Baiker, A. J. Mol. Catal. A: Chem. 2009, 57e62 and references herein (b) Zhu,
B.; Lazar, M.; Trewyn, B. G.; Angelici, R. J. J. Catal. 2008, 260, 1e6; (c) Zhu, B.;
Angelici, J. Chem. Commun. 2007, 2157e2159; Dirhodium caprolactama-
te/tBuOOH: Choi, H.; Doyle, M. P. Chem. Commun. 2007, 745e747; (d) IBX:
Nicolaou, K. C.; Mathison, C. J. N.; Montagnon, T. Angew. Chem., Int. Ed. 2003, 42,
300 MHz):
d
¼5.50 (tq, J¼1.2, 6.3 Hz, 1H), 4.67 (m, 1H), 4.35 (dd,
J¼6.3, 12.0 Hz, 1H), 4.06 (dd, J¼6.9, 12.0 Hz, 1H), 3.87 (m, 1H), 3.41
(m, 1H), 2.10 (td, J¼7.2, 15.2 Hz, 4H), 1.85 (q, J¼7.3 Hz, 2H), 1.48 (s,
3H), 1.63e1.26 (m, 6H), 0.90 (t, J¼7.2 Hz, 3H). 13C NMR (CDCl3,
ꢀ
4077e4082; (e) Ru-catalyst in the presence of a quinone: Ell, A. H.; Samec, J. S.
€
M.; Brasse, C.; Backvall, J.-E. Chem. Commun. 2002, 1144e1145; (f)
75 MHz):
d
¼210.9 (C), 138.7 (C), 121.0 (CH), 97.9 (THPeCH), 63.5
CuBr2eLiOtBu: Yamaguchi, J.-I.; Takeda, T. Chem. Lett. 1992, 1933e1936.
13. Newcomb, M.; Burchill, M. T. J. Am. Chem. Soc. 1984, 106, 2450e2451.
14. Reviews: (a) Negri, G.; Kascheres, C.; Kascheres, A. J. J. Heterocycl. Chem. 2004, 41,
461e491; (b) Elassar, A.-Z. A.; El-Khair, A. A. Tetrahedron 2003, 59, 8463e8480.
15. Niphakis, M. J.; Turunen, B. I.; Georg, G. I. J. Org. Chem. 2010, 75, 6793e6805.
16. (a) For a review: Ferraz, H. M. C.; Gonc¸ alo, E. R. S. Quim. Nova 2007, 4, 957e964;
(b) For some more recent publications in this area, see: Al-Mousawi, S. M.; El-
Apasery, M. A.; Elnagdi, M. H. Molecules 2010, 15, 58e67.
(CH2), 62.3 (CH2), 40.5 (CH2), 35.9 (CH2), 33.3 (CH2), 30.7 (CH2), 25.6
(CH2), 19.6 (CH2), 16.5 (CH3), 7.8 (CH3).
4.21. (E)-8-Hydroxy-6-methyloct-6-en-3-one (40)
17. Recent examples: (a) Arrad, M. A.; Outtouch, R.; Ait Ali, M.; El Firdoussi, L.;
Karim, A.; Roucoux, A. Catal. Commun. 2010, 11, 442e446; (b) Zhang, Z.-H.; Li, T.-
To a solution of 39 (100 mg, 0.41 mmol) in 1 mL of MeOH was
added 10.0 mg PPTS (0.04 mmol, 0.1 equiv) under nitrogen and the
reaction mixture was refluxed for 2 h when no more starting ma-
terial remained. The solvent was evaporated and the residue di-
luted with Et2O. The resulting precipitate was filtrated on a plug of
Celite. The ether solution was washed with brine and dried with
Na2SO4 followed by evaporation giving 55 mg of 40 (84%, E/Z 4:1),
which was not purified. 1H NMR (CDCl3, 250 MHz, signals for the
~
S.; Li, J.-J. Catal. Commun. 2007, 8, 1615e1620; (c) Sridharan, V.; Avendano, C.;
ꢀ
Menendez, J. C. Synlett 2007, 881e884 See also references cited therein.
18. Some examples (a) Kigoshi, H.; Hayashi, N.; Uemura, D. Tetrahedron Lett. 2001, 42,
7469e7471; (b) Keller, H.; Schlosser, M. Tetrahedron 1996, 52, 4637e4644; (c) Bar-
toli, G.; Cimarelli, C.; Palmieri, M.; Bosco, M.; Dalpozzo, R. Synthesis 1990, 895e897.
19. Mangelinckx, S.; Giubellina, N.; De Kimpe, N. Chem. Rev. 2004, 104, 2353e2399.
20. Longhi, K.; Moreira, D. N.; Marzari, M. R. B.; Floss, V. M.; Bonacorso, H. G.;
Zanatta, N.; Martins, M. A. P. Tetrahedron Lett. 2010, 51, 3193e3196.
ꢁ
21. Borzatta, V.; Capparella, E.; Chiappino, R.; Impala, D.; Poluzzi, D.; Vaccari, A.
major E-isomer)
d
¼5.39 (ddt, J¼1.2, 2.5, 6.9 Hz, 1H), 4.12 (d,
Catal. Today 2009, 140, 112e116.
22. Graves, C. R.; Zeng, B.-S.; Nguyen, S. T. J. Am. Chem. Soc. 2006, 128, 12596e12597.
23. Ishihara, K.; Kurihara, H.; Yamamoto, H. J. Org. Chem. 1997, 62, 5664e5665.
24. Adkins, H.; Elofson, R. M.; Rossow, A. G.; Robinson, C. C. J. Chem. Soc. 1949, 71,
3622e3629.
25. For recent studies on these lithium species, see: Ma, Y.; Collum, D. B. J. Am.
Chem. Soc. 2007, 129, 14818e14825; Liao, S.; Collum, D. B. J. Am. Chem. Soc.
2003, 125, 15114e15127.
J¼6.7 Hz, 2H), 2.54 (m, 2H), 2.44 (q, J¼7.3 Hz, 2H), 2.30 (m, 2H), 1.66
(s, 3H), 1.03 (t, J¼7.3 Hz, 3H). 1H NMR (C6D6, 400 MHz)
¼5.30 (ddt,
d
J¼1.2, 2.4, 6.4 Hz, 1H), 3.99 (d, J¼6.8 Hz, 2H), 2.16 (br t, 2H), 2.06 (m,
2H), 1.91 (q, J¼7.3 Hz, 2H), 1.40 (s, 3H), 0.90 (t, J¼7.3 Hz, 3H). 13C
NMR (CDCl3, 63 MHz)
d
¼210.9 (C), 138.1 (C), 123.8 (CH), 59.2 (CH2),
40.5 (CH2), 35.9 (CH2), 33.2, (CH2), 16.3 (CH3), 7.8 (CH3). HRMS (DI,
EI) calcd for [C9H16NaO2] m/z 179.1048, found 179.1043. The data for
39 and 40 are in agreement with the literature.29
26. For a review on alkylation of metallated imines: Whitesell, J. K.; Whitesell, M. A.
Synthesis 1983, 517e537.
27. Due to the volatility of the oxido-reduction pivaldehyde/neopentyl alcohol pair,
no accurate conversion rates could be obtained from NMR analysis as before.
Optimization of the amount of pivaldehyde to be added was done by moni-
toring the electrophile conversion by NMR. Two equivalents of oxidant were
employed.
Acknowledgements
28. Dybas, R. A.; Grier, N.; Witzel, B. E., U.S. Patent 4,070,400, 1978.
ꢀ
29. Cosse, A. A.; Bartelt, R. J.; Zilkowski, B. W. J. Nat. Prod. 2002, 65, 1156e1160.
€
Thanks are due to Prof. Joelle Prunet (University of Glasgow) for
30. Van, T. N.; De Kimpe, N. Tetrahedron 2000, 56, 7969e7973.
31. Ooi, T.; Otshuka, H.; Miura, T.; Ichikawa, H.; Maruoka, K. Org. Lett. 2002, 4,
2669e2672.
helpful discussions. Ecole Polytechnique (France) is gratefully ac-
knowledged for a PhD grant to A.C.