S. Jones, I. Wilson / Tetrahedron Letters 47 (2006) 4377–4380
4379
Table 2. Flash vacuum pyrolysis of lactones 4–10
thesis of 3-(substituted) furan-2(5H)-ones that over-
comes the stereoselectivity issues and excess reagents
used when employing cyclopentadiene adducts.
O
O
R
FVP
500 oC
Supplementary data
O
R
O
A list of experimental procedures and characterisation
data for all new compounds is included. Supplementary
data associated with this article can be found, in the on-
4-10
12-18
Entry
Lactone
Product
12
R
Yielda
1
2
3
4
5
6
7
4
CH3
78
5
13
14
15
16
17
18
CH2@CHCH2
CH2@CHCH2CH2
PhCH2
83
70
79
78b,c
67c
82
References and notes
6
7
1. (a) Bernstein, J.; Shmeuli, U.; Zadock, E.; Kashman, Y.;
Neeman, I. Tetrahedron 1974, 30, 2817–2824; (b) Miya-
kadao, M.; Kato, T.; Ohno, N.; Yoshioka, H.; Ohshio, H.
Agric. Biol. Chem. 1977, 41, 57–64.
8
H
9
10
(EtO)2P(O)
(CH3)3Si
a Based on isolated product.
2. (a) Carter, N. B.; Nadany, A. E.; Sweeney, J. B. J. Chem.
Soc., Perkin Trans. 1 2002, 2324–2342; (b) Marshall, J. A.;
Wolf, E. M.; Wallace, E. M. J. Org. Chem. 1997, 66, 367–
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3945; (d) Bassetti, M.; D’Annibale, A.; Fanfoni, A.;
Minissi, F. Org. Lett. 2005, 7, 1805–1808.
b 2(5H)-Furanone obtained instead of vinyl stannane.
c Refers to conversion to product as noted from the 1H NMR
spectrum.
3. (a) Canonne, P.; Akssira, M.; Lemay, G. Tetrahedron Lett.
1983, 24, 1929–1932; (b) Cannone, P.; Akssira, M.; Fytas,
G. Tetrahedron 1984, 40, 1809–1815; (c) Corbera, J.; Font,
lysis at ꢀ500 °C readily cycloreverted lactones 4–7 to
yield 3-alkyl butenolides 12–15 in good to excellent
yields (Table 2, entries 1–4) that are generally compara-
ble to those obtained with the cycloadduct of cyclopent-
adiene. Interestingly, the homo-allyl lactone 14 (Table 2,
entry 3) did not appear to undergo a Cope rearrange-
ment under the FVP conditions.
J.; Monsalvatje, M.; Ortuno, R. M.; Sanchez-Ferrando, F.
˜
J. Org. Chem. 1988, 53, 4393–4395.
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2001, 12, 1117–1119; (b) Atherton, J. C. C.; Jones, S.
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C.; Jones, S. J. Chem. Soc., Perkin Trans. 1 2002, 2166–
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Lett. 2000, 2, 2527–2530; (f) Corbett, M. S.; Liu, X.;
Sanyal, A.; Snyder, J. K. Tetrahedron Lett. 2003, 44, 931–
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W.; Snyder, J. K. Org. Lett. 2005, 7, 31–34; (h) Snyder, A.;
Yuan, Q.; Snyder, J. K. Tetrahedron Lett. 2005, 46, 2475–
2478; (i) Burgess, K. L.; Corbett, M. S.; Eugenio, P.;
Lajkiewicz, N. J.; Liu, X.; Sanyal, A.; Yan, W.; Yuan, Q.;
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5. Jenkitkaemwong, Y.; Thebtaranonth, Y.; Wajirum, N.
Tetrahedron Lett. 1979, 20, 1615–1618.
Somewhat disappointingly, stannane 8 failed to survive
FVP treatment and afforded only destannylated fura-
none 16 in good conversion together with unidentified
decomposition products (entry 5). However, attempts
to purify this material led to loss of product, presumably
due to the inherent volatility of the lactone 16. Vinyl
stannanes have been previously prepared using FVP
techniques, although these have been unsubstituted,
inferring that the a-stannyl enones prepared here are
thermally unstable.14 More encouraging results were
obtained with the phosphonate 9, leading to quantita-
tive cleavage to the vinyl phosphonate 17 (entry 6).
However, this material could not be isolated, decompo-
sition occurring on attempted purification by silica gel
chromatography or Kugelro¨hr distillation. Phosphonate
17 has been previously prepared via an oxidative desel-
enation procedure, however, this compound was found
to decompose by polymerisation even while standing
at room temperature.15 In spite of the problems with
the two previous a-hetero substituted lactones, the C-
trimethylsilyl lactone 10 cleanly afforded 3-(trimethylsi-
lyl) 2(5H)-furanone 18 in excellent yield (entry 7).
Although a few other routes exist to vinyl silanes of this
type,16 this two-step C-silylation/retro Diels–Alder
sequence represents a simpler and more efficient route
than those currently employed.
6. Trost, B. M.; Vidal, B.; Thommen, M. Chem. Eur. J. 1999,
5, 1055–1069.
7. Cycloadducts 5–10 are all new compounds and have been
fully characterised. See Supplementary data for full
details.
8. (a) Rathke, M. W.; Sullivan, D. F. Synth. Commun. 1973,
3, 67–72; (b) Kruger, C. R.; Rochow, E. G. J. Organomet.
¨
Chem. 1964, 1, 476–483; (c) Ainsworth, C.; Chen, F.; Kuo,
Y. J. Organomet. Chem. 1972, 46, 59–71; (d) Ainsworth,
C.; Kuo, Y. J. Organomet. Chem. 1972, 46, 73–87; (e)
Paterson, I.; Fleming, I. Tetrahedron Lett. 1979, 20, 993–
994.
9. Larson, G. L.; Fuentes, L. M. J. Am. Chem. Soc. 1981,
103, 2418–2419.
10. Bagheri, V.; Doyle, M. P.; Taunton, J.; Claxton, E. E. J.
Org. Chem. 1988, 53, 6158–6160.
11. Minimised structures were generated using PM3 calcula-
tions with Chem3D Ultra version 8.0.3.
In summary, we have demonstrated that bridgehead
lactones of type 3 can indeed be deprotonated and func-
tionalised with a variety of electrophilic species. This has
led to a much improved and efficient route for the syn-
12. De Keyser, J.-L.; De Cock, C. J. C.; Poupaert, J. H.;
Dumont, P. J. Org. Chem. 1988, 53, 4859–4862.
13. Garrigues, P.; Garrigues, B. C.R. Acad. Sci. Paris, IIC
1998, 545–550.