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Organic syntheses vol 58 - Sheppard W.A.

Sheppard W.A., Buchi G.H. Organic syntheses vol 58 - Wiley, 1978. - 123 p.
Download (direct link): organicsynthesesvol581978.pdf
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Pure crystalline 2,3-dicyanobutadiene has been prepared in high yield by gas-phase thermolysis of cyclobutene (2).2,8 Analogous thermolysis of derivatives of cyclobutene- 1,2-dicarboxylic acid appears to represent general procedures for the synthesis of derivatives of butadiene-2,3-dicarboxylic acid of high purity.2,12 These
2,3-DICYANOBUTADIENE AS A REACTIVE INTERMEDIATE
73
TABLE I
[4 + 2]-Cyclo addition Reactions of 2,3-Dicyanobutadiene Formed in situ from 1,2-Dicyanocyclobutene2
Temp-
Yield erature Time
Olefin Product (%)“ CO (hours)
Norbornadiene 4,5-Dicyanotricyclo- [6.2.1.02,7]undeca-
4,9-diene 79” 150 12
Acenaphthylene 8,9-Dicyano-6b,7,10,10a-
tetrahydrofluoranthene 77 138 48
Cyclopentene 3,4-Dicy anobicyclo[4.3.0]-
non-3-ene 65 135 16
Ethylene 1,2-Dicyanocyclohexene 58 135 16
(E)-Stilbene l,2-Dicyano-4,5-diphenyl-
cyclohexene 32 138 24
Butyl vinyl 1,2-Dicyano-4-butoxy-
ether cyclohexene 28 155 16
(E)-l,2-Dichloro- 1,2-Dicyano-4,5- trans -
ethylene dichlorocyclohexene 8 135 16
2-Vinylpyridine l,2-Dicyano-4-(2'-pyridyl)-
cyclohexene 5 138 48
“ Yields of analytically pure products are given.
h A 70:24 mixture of exo and endo isomers. Some 2:1 cycloadduct was also isolated (2.4% yield).
butadienes take part in [4 + 2]-cycloaddition reactions either as reactive dienes2,13’14 or as reactive dienophiles.2,14 In the pure state, however, they tend to polymerize, and even crystalline 2,3-dicyanobutadiene slowly polymerizes to yield a highly cross-linked polymer without losing its original crystal form. A [2 + 4]-dimer of a 2,3-dicyanobutadiene is also formed by heating the dicyanocy-clobutene in solution with a polymerization inhibitor.2 Monomeric derivatives of butadiene-2,3-dicarboxylic acid cannot be prepared in solution due to rapid dimerization.814
The present procedure of in situ generation and trapping of
2,3-dicyanobutadiene in the presence of olefins overcomes these problems and affords the [4 + 2]-cycloadducts in good yields, particularly in the case of olefins possessing a strained double bond.2 Substituted 1,2-dicyanocyclohexenes prepared by the in situ [4 + 2]-cycloadditions can be dehydrogenated to new aromatic orfho-dinitriles. For example, 2,3-dicyanofluorene is prepared in
74
ORGANIC SYNTHESES—VOL. 58
56% yield by heating 2,3-dicyano-l,4,4a,9a-tetrahydrofluorene (3) at 200° in dimethylmaleate in the presence of 5% palladium on charcoal. Other aromatic ortho-dinitriles have also been prepared by this method.2 Because 2,3-dicyanobutadiene is an electron-deficient diene, it does not react with electron-deficient olefins, such as maleic anhydride and fumaronitrile,2,8 with this procedure. However, by generating the dicyanobutadiene in refluxing chlorobenzene in the presence of maleic anhydride with 2,5-di-terf-butylbenzoquinone inhibitor, the [2 + 4]-cyclic dicarbonitrile adduct, m.p. 201-202.5°, was formed in a yield of 38%.15
1. Central Research Laboratories, Ciba-Geigy A G, CH-4002 Basel, Switzerland.
2. D. Bellus, K. von Bredow, H. Sauter, and C. D. Weis, Helv. Chim. Acta, 56, 3004
(1973).
3. D. Bellus and G. Rist, Helv. Chim. Acta, 57, 194 (1974).
4. D. Bellus, H.-C. Mez, and G. Rihs, J. Chem. Soc., Perkin Trans. II, 884 (1974).
5. D. Bellus, H.-C. Mez, G. Rihs, and H. Sauter. J. Amer. Chem. Soc.. 96, 5007 (1474).
6. R. Wehrli, H. Schmid, D. Bellus, and H.-J. Hansen, Helv. Chim. Acta, 60, 1325 (1977).
7. H.-D. Martin, M. Hekman, G. Rist, H. Sauter, and D. Bellus, Angew. Chem., 89, 420 (1977).
8. D. Bellus and C. D. Weis, Tetrahedron Lett., 999 (1973).
9. H. Prinzbach and H.-D. Martin, Chimia, 23,37 (1969).
10. J. L. Greene and M. Godfrey, U.S. Patent 3,336,354 (1967) [C.A., 68, 21598v (1968)].
11. J. L. Greene, N. W. Standish, and N. R. Gray, U.S. Patent 3,275,676 (1966) [C.A., 66, 10637y (1967)].
12. P. Dowd and K. Kang, Synth. Commun., 4, 151 (1974).
13. E. Vogel, Justus Liebigs Ann. Chem., 615, 14 (1958).
14. U.-I. Zahorszky and H. Musso, Justus Liebigs Ann. Chem., 1777 (1973).
15. W. A. Sheppard, unpublished results.
Appendix
Chemical Abstracts Nomenclature (Collective Index Number; Registry Numbers)
1.2-Dicyanocyclobutane: 1,2-Cyclobutanedicarbonitrile (8,9); (3396-17-6)
1-Chloro-1,2-dicyanocyclobutane: 1,2-Cyclobutanedicarbonitrile,
1-chloro- (8,9); (3716-98-1)
1.2-Dichloro-l ,2-dicyanocyclobutane: 1,2-Cyclobutanedicarbo-nitrile, 1,2-dichloro- (8,9); (3496-67-1)
1.2-Dicyanocyclobutene: 1-Cyclobutene- 1,2-dicarbonitrile (8,9); (3716-97-0)
FLUORINATIONS WITH PYRIDINIUM POLYHYDROGEN FLUORIDE 75
2.3-Dicyanobutadiene: Succinonitrile, dimethylene- (8); Butane-dinitrile, bis(methylene)- (9); (19652-57-4)
2.3-Dicyanofluorene: 2,3-Fuorenedicarbonitrile (8); 9H-Fluo-rene-2,3-dicarbonitrile (9); (52477-74-4)
Cyclobutene-l,2-dicarboxylic acid: l-Cyclobutene-l,2-dicarbox-ylic acid (8,9); (16508-05-7)
Cyclobutene- 1,2-dicarboxamide: 1 -Cyclobutene- 1,2-dicarbox-amide (8,9); (23335-15-1)
Butadiene-2,3-dicarboxylic acid: Succinic acid, dimethylene- (8); Butanedioic acid, bis(methylene)- (9); (488-20-0)
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