- An efficient bismuth(III) chloride-catalyzed synthesis of 1,1-di-arylalkenes via Friedel-Crafts reaction of acyl chloride or vinyl chloride with arenes
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In the presence of catalytic amount of bismuth(III) chloride, the reactions of acyl chlorides or vinyl chlorides with arenes afforded 1,1-diarylalkenes in 25-82% isolated yield. In the case of the reaction of acyl chlorides with arenes, the procedure includes an initial Friedel-Crafts acylation, subsequent formation of vinyl chlorides and final Friedel-Crafts-type vinylation of another arene molecule with vinyl chloride. This paper reports the first Lewis acid-catalyzed cleavage of the C-Cl bond of vinyl chloride and its application in the synthesis of multiply subtituted alkenes.
- Sun, Hongbin,Hua, Ruimao,Chen, Songjie,Yin, Yingwu
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p. 1919 - 1925
(2007/10/03)
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- Ortho Methyl Group Effects in Cumyl Systems
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In an attempt to evaluate the steric effect of ortho methyl groups on the stability of the cumyl radical, 2,2',4,4',6,6'-hexamethylazocumene (6) was synthesized and its rate of decomposition was measured.The fact that 6 decomposes 40 times faster than azocumene is attributed to a ground state steric effect.Calculations on the mesitylcumyl radical 1 and cation 2 show both systems to be substantially nonplanar with dihedral angles of 48 deg and 35 deg, respectively.Calculated charge distributions for cation 2 corroborate previously obtained NMR results which showed substantial loss of charge delocalization.
- Timberlake, Jack W.,Pan, Dawei,Murray, Jane,Jursic, Branko S.,Chen, Tonghua
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p. 5295 - 5298
(2007/10/02)
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- A Novel Friedel-Crafts Reaction of Hindered Ketones
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Mesitylene has been shown to react with acetyl chloride in the presence of aluminium chloride to form 1,1-dimesitylethene.Acetomesitylene has been demonstrated to be an intermediate in the reaction, which proceeds in the second step by nucleophilic attack by the arene on the carbonyl group of acetomesitylene, which is activated by the formation of a polarized complex with aluminum chloride.Mesitylene reacts similarly with propionyl chloride, forming 1,1-dimesitylpropene; propiomesitylene is an intermediate.Steric and electronic factors responsible for this unique Friedel-Crafts reaction are discussed.
- Roberts, Royston M.,El-Khawaga, Ahmed M.,Roengsumran, Sophon
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p. 3180 - 3183
(2007/10/02)
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