948
P. Areces et al.
SHORT PAPER
HMRS (FAB+): m/z calcd for C11H14O4 + H: 211.097034; found:
ma de Extremadura (Grant nº 2PR02A016) for financial support.
One of us (E.C.) thanks the Ministerio de Educación y Ciencia for
a doctoral fellowship.
211.097057 (M + H)+.
Anal. Calcd for C11H14O4: C, 62.84; H, 6.71. Found: C, 62.56; H,
6.97.
References
(2E)-2-Acetoxy-5-hydroxy-6-propanoylhepta-1,3,6-triene (8b)
Method A: Treatment of aldehyde 6 (0.75 g, 3.75 mmol) with ethyl
vinyl ketone (3.7 mL, 37.5 mmol) in the presence of DABCO was
carried out by following Method A as described above for 8a, ex-
cept that the process lasted 6 days. Purification by flash chromatog-
raphy (hexane–EtOAc, 3:1) gave 8b as an oil; yield: 0.82 g (50%).
(1) See, for instance: (a) The Chemistry of Functional Groups:
The Chemistry of Dienes and Polyenes, Vol. 2; Rappoport,
Z., Ed.; Wiley: Chichester, 2000. (b) Vasil’ev, A. A.;
Serebryakov, E. P. Russ. Chem. Rev. 2001, 70, 830.
(2) See, for instance: (a) Corey, E. J. Angew. Chem. Int. Ed.
2002, 41, 1650. (b) Nicolau, K. C.; Snyder, S. A.;
Montagnon, T.; Vassilikogiannakis, G. Angew. Chem. Int.
Ed. 2002, 41, 1668.
(3) See, for instance: (a) Donaldson, W. A. Curr. Org. Chem.
2000, 4, 837. (b) Knolker, H. J.; Brauer, A.; Brocher, D. J.;
Cammerer, S.; Frohner, W.; Gouser, P.; Hermann, H.;
Herzberg, D.; Reddy, K. R.; Rohde, G. Pure Appl. Chem.
2001, 73, 1075.
(4) For synthetic uses of pentadienal derivatives as iron
tricarbonyl complexes, see: (a) Review: Gree, R. Synthesis
1989, 341. (b) See also: Wang, J. L.; Ueng, C. H.; Cheng, J.
S.; Yeh, M. C. Organometallics 1994, 13, 4453. For the
synthesis of differently substituted (2E,4E)-5-bromopenta-
2,4-dienal, see: (c) Vicart, N.; Castet-Caillabct, D.;
Ramondene, Y.; Ple, G.; Duhamel, L. Synlett 1998, 411; and
references cited therein. For the electrocyclization reactions
of penta-2,4-dienal derivatives, see: (d) Rodríguez-Otero,
J.; Cabaleiro-Lago, E. M. Chem. Eur. J. 2003, 9, 1837.
(e) Rodríguez-Otero, J. J. Org. Chem. 1999, 64, 6842.
(5) Román, E.; Serrano, J. A.; Cuéllar, M. E.; Marfil, A.; Galbis,
J. A. J. Carbohydr. Res. 1992, 11, 1.
Method B: By using Method B as described above for 8a, com-
pound 7 was converted into 8b by treatment with ethyl vinyl ketone,
except that the process lasted 6 days; yield: 50%.
IR (film): 3500 m, 2980 m, 2980 m, 1760 s, 1678 s, 1205 cm–1 s.
1H NMR (400 MHz, CDCl3): d = 6.25 (dd, 1 H, J3,5 = 1.6 Hz, J3,4
=
16 Hz, H-3), 6.14 (s, 1 H, H-1b), 5.99 (s, 1 H, H-1a), 5.80 (dd, 1 H,
J4,3 = 16 Hz, J4,5 = 1.6 Hz, H-4), 5.10 (d, 1 H, J5,OH = 6 Hz, OH), 5.03
(d, 1 H, J7a,7b = 1.6 Hz, H-7a), 4.92 (d, 1 H, J7a,7b = 1.6 Hz, H-7b),
2.98 (br s, 1 H, OH), 2.74 (q, 2 H, J2¢,3¢ = 7.6 Hz, H-2¢), 2.22 (s, 3 H,
OCOCH3), 1,11 (t, 3 H, J2¢,3¢ = 7.2 Hz, H-3¢).
13C NMR (100 MHz, CDCl3): d = 202.7 (CH3CO), 168.7
(CH3COO), 151.0 (C-6), 148.0 (C-2), 131.2 (C-4), 125.3 (C-1),
124.6 (C-3), 106.0 (C-7), 70.2 (C-5), 31.3 (C-2¢), 20.7 (CH3COO),
7.9 (CH3CH2).
Anal. Calcd for C12H16O4: C, 64.27; H, 7.19. Found: C, 64.14; H,
6.98.
(2E)-2-Acetoxy-5-hydroxy-6-methoxycarbonylhepta-1,3,6-
triene (8c)
Method A: Treatment of aldehyde 6 (0.75 g, 3.75 mmol) with meth-
yl acrylate (3.4 mL, 37.5 mmol) in the presence of DABCO was car-
ried out by following Method A as described above for 8a, except
that the process lasted 27 days. Purification by flash chromatogra-
phy (hexane–EtOAc, 3:1) allowed the isolation of starting material
6 (0.13 g) and 8c as an oil; yield: 0.51 g (48%).
(6) Deprotonation at position 4 in compound 3 to give a
conjugate carbanion followed by departure of the acetoxy
group (E1cB mechanism) at position 5 appears to be the
most probable reaction path. See ref. 5.
(7) For the latest review on MBH reaction, see: (a) Basavaiah,
R.; Rao, A. J.; Satyanarayana, T. Chem. Rev. 2003, 103,
811. For synthetic applications of the MBH adducts, see:
(b) Kim, J. N.; Lee, K. Y. Curr. Org. Chem. 2002, 10, 627.
For short reviews on the synthetic applications of DABCO
with special attention to the MBH reaction, see:
Method B: By using Method B as described above for 8a, com-
pound 7 was converted into 8c by treatment with methyl acrylate,
except that the process lasted 27 days; yield: 0.16 g (31%).
IR (film): 3500 m, 3020 m, 1760 s, 1720 s, 1200 cm–1 s.
(c) Mallavadhani, U. V. In Encyclopedia of Reagents for
Organic Synthesis, Vol. 2; Paquette, L. A., Ed.; Wiley: New
York, 2003, 1494. (d) Kannan, V. Synlett 2004, 1120.
(8) The MBH reaction using a,b-unsaturated aldehydes is a well
known reaction, see ref. 7. However, the MBH reaction of a
formylbutadiene compound has, to the best of our
knowledge, never been described. On the other hand, formal
MBH adducts derived from a,b-unsaturated sugar aldehydes
have been synthesized in two steps, see: (a) Pathak, R.;
Shaw, A. K.; Bhaduri, A. P. Tetrahedron 2002, 58, 3535.
For other MBH reactions of carbohydrate derivatives, see:
(b) Krishna, P. R.; Kannan, V.; Ilangovan, A.; Sharma, G. V.
M.; Rao, M. H. V. R. Synlett 2003, 888. (c) Krishna, P. R.;
Sekhar, H. J.; Kannan, V. Tetrahedron Lett. 2003, 44, 4973.
(9) González, F.; Lesage, S.; Perlin, A. S. Carbohydr. Res. 1975,
42, 267.
1H NMR (400 MHz, CDCl3): d = 6.30 (s, 1 H, H-1b), 6.28 (dd, 1 H,
J3,5 = 1.2 Hz, J3,4 = 15.6 Hz, H-3), 5.91 (s, 1 H, H-1a), 5.84 (dd, 1
H, J4,3 = 16 Hz, J4,5 = 6 Hz, H-4), 5.10 (br s, 1 H, H-5), 5.06 (d, 1 H,
J7a,7b = 0.8 Hz, H-7a), 4.95 (d, 1 H, J7a,7b = 0.8 Hz, H-7b), 3.80 (s, 3
H, OCH3), 3.48 (d, 1 H, JOH,5 = 3.6 Hz, OH), 2.24 (s, 3 H,
CH3COO).
13C NMR (100 MHz, CDCl3): 168.6 (OCOCH3), 166.3 (COOCH3),
150.9 (C-6), 140.7 (C-2), 130.8 (C-4), 125.9 (C-1), 124.8 (C-3),
106.1 (C-7), 70.1 (C-5), 51.8 (OCOCH3), 20.6 (CH3COO).
Anal. Calcd for C11H14O5: C, 58.40; H, 6.24. Found: C, 58.01; H,
6.62.
Acknowledgment
We thank the Dirección General de Investigación Científica y Téc-
nica (Grant nº BQU2003-04967-C02-01) and Comunidad Autóno-
Synthesis 2006, No. 6, 946–948 © Thieme Stuttgart · New York