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Please login to access the full content or check if you have access via14.1.1.1.1 Method 1: [C1 + C3 + C1] Diacylation of Propene and Higher Alkenes
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Balaban, T. S.; Balaban, A. T., Science of Synthesis, (2003) 14, 25.
The acylation of alkenes catalyzed by Lewis or Brønsted acids has been studied for more than a century.[95] For example, it is known that 2-methylpropene (isobutylene) affords 4-methylpent-3-en-2-one on monoacetylation. The discovery that its diacetylation furnished 2,4,6-trimethylpyrylium salts was made independently in 1959 by Balaban and Nenitzescu in Romania,[19] and Praill in England.[18] Later it was shown that the aluminum trichloride catalyzed reaction between acetyl chloride and tert-butyl chloride, followed by decomposition of the reaction mixture with water, allowed the isolation of the triacetylation product of 2-methylpropene (a vinylogous 4-pyrone),[96] and, finally, Roussel found that decomposition of the same mixture with liquid ammonia resulted in a tetraacetylation product, isolated as the 2,7-diazanaphthalene (no dioxonia analogue could be isolated).[97–99] Actually, it was shown that the tetraacylation product is formed first and is then deacylated to the triacylation product. It is interesting to mention that the discovery of this reaction in Bucharest[19] occurred serendipitously during a one-pot assembly of five synthons: 2,6-di-tert-butyl-4-methylpyrylium salts were isolated in low yields from the reaction of aluminum trichloride with tert-butyl chloride and carbon monoxide under pressure. 2-Methylpropene was diacylated by the pivaloyl cation intermediate, formed from carbon monoxide and the tert-butyl cation.[19]
References
[18] | Meeeee, M. M. M.; Meeeeee, M. M., M. Meee. Mee., (8888), 8888. |
[19] | Meeeeee, M. M.; Meeeeeeeee, M. M., Meeeee Meeeeee Mee. Meee., (8888) 888, 88. |
[95] | Meeeeee, M. M.; Meeeeeeeee, M. M., Me Meeeeee–Meeeee eee Meeeeee Meeeeeeee, Meee, M. M., Me.; Meeee-Meeeeeeeeeee: Mee Meee, (8888); Mee. 8, e 8888. |
[96] | Meeeeee, M. M.; Meeeeeeee, M. M.; Meeeeeeee, M. M.; Meeeeeeeee, M. M., M. Meee. Mee., (8888), 8888. |
[97] | Meeé, M.; Meeeee, M.; Meeee, M.; Meeeeee, M., Meeeeeeeeee Meee., (8888) 88, 888. |
[98] | Meeé, M.; Meeeeee, M., Meee. Mee. Meee. Me., (8888), 888. |
[99] | Meeé, M.; Meeeeee, M., Meee. Mee. Meee. Me., (8888), 888. |
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- 8.Meeeee-Meee, (8888) M 8e, 888.