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Olefin coupling of 2-Methylene-1,3-diselenole; Tetraselenafulvalene

SyntheticPage 417
DOI: 10.1039/SP417
Submitted May 28, 2010, published May 28, 2010
Nikola Paul Chmel (n.chmel@warwick.ac.uk)
A contribution from Scott group, Warwick University


			Reaction Scheme: Olefin coupling of <SPAN class=csm-chemical-name id=csm1288647393415 title=2-Methylene-1,3-diselenole>2-Methylene-1,3-diselenole</SPAN>

Chemicals Used

2-Methylene-1,3-diselenole synthesis
Iodine
Morpholine (dried over CaH2, degassed)
DMF (distilled over calcium hydride, degassed)

Procedure

All of the operations were performed in the dark. Iodine (2.5 g, 9.8 mmol) was dissolved in the solution of dry morpholine (2.7 g, 31 mmol) in dry DMF (40 ml) under argon. 2-Methylene-1,3-diselenole (1.0 g, 4.8 mmol) in dry DMF (25 ml) was added to the mixture cooled in water bath and was stirred for 1 h at ambient temperature. The reaction was quenched with water (20 ml) and extracted with DCM (4 × 15 ml). The combined organic extracts were washed with aqueous Na2S2O3 (2 × 50 ml) and water (3 × 20 ml), and dried over anhydrous Na2SO4. The solvents were removed in vacuo (without heating). The residue was purified on column using DCM:hexane (1:2) mixture as eluent. The obtained product was additionally recrystallised from hexane. Yield 80 mg (4%).

Author's Comments

Reaction performed several times with similar yields - the literature yields are ~30% - we haven't been able to reproduce that. 100 mg quantities are satisfactory for my use, but ideas how to improve the yield are appreciated. As far as I'm aware - the mechanism of this reaction is unknown.

Data

Elemental analysis found (calculated for C6H4Se4) %: C 18.21 (18.39), H 1.13 (1.03), N >0.1 (0.0)
1
H NMR (400 MHz, 298 K, CDCl3) δH 7.21 (s, 4H, CH=CH)
13
C NMR (100 MHz, 298 K, CD2Cl2) δC 123.0 (CH=CH), 107.0 (C=C)
MS (ESI+) m/z 393.2 ([M]+)

Lead Reference

K. Takimiya, H. J. Jeon and T. Otsubo, Synthesis, 2005, 2005, 2810-2813.

Other References

Y. A. Jackson, C. L. White, M. V. Lakshmikantham and M. P. Cava, Tetrahedron Lett., 1987, 28, 5635-5636

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Keywords: alkenes, heterocyclic compounds, metathesis, oxidation, selenium

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