- Versatile and fluoride-free cyanation of alkyl halides and sulfonates with trimethylsilyl cyanide
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Cyanation of biphenyl-4-ylmethyl methanesulfonate with trimethylsilyl cyanide using fluoride-free inorganic salts, such as Cs2CO 3, K2CO3, and LiOH·H2O, as additives in MeCN quantitatively gave biphenyl-4-ylacetonitrile. This methodology was applied to various alkyl halides to give the corresponding nitrile compounds in good to excellent yields. Of note, 4-(hydroxymethyl) benzyliodide O-protected by the silyl group was converted into phenylacetonitrile derivative in 99% yield without desilylation. Georg Thieme Verlag Stuttgart.
- Yabe, Osamu,Mizufune, Hideya,Ikemoto, Tomomi
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experimental part
p. 1291 - 1294
(2009/10/23)
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- Ultrafast study of p-biphenylyldiazomethane and p-biphenylylcarbene
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p-Biphenylyldiazomethane was excited by femtosecond pulses of UV light in acetonitrile, in cyclohexane, and in methanol. Ultrafast photolysis produces a singlet excited state of p-biphenylyldiazomethane with λmax = 490 nm, and lifetimes of less than 300 fs in acetonitrile, in cyclohexane, and in methanol. The decay of the excited state is accompanied by the growth of transient absorption with λmax = 360 nm. The carrier of this transient absorption is attributed to singlet p-biphenylylcarbene, a result that is consistent with the predictions of TD-DFT calculations. The singlet carbene lifetimes are 200 and 77 ps in acetonitrile and cyclohexane, respectively, and are controlled by intersystem crossing to the lower energy triplet state. The transient absorption does not decay to baseline in acetonitrile, because of the formation of nitrile ylide. The equilibrium mixture of singlet and triplet p-biphenylylcarbene reacts with acetonitrile to form a nitrile ylide (λmax = 370 nm), and with cyclohexane by C-H insertion 1-20 ns after the laser pulse. The singlet carbene lifetime is only 7.9 ps in methanol, owing to a rapid reaction with the solvent. Reaction with the solvent gives rise, in part, to a p-biphenylylbenzyl cation (λmax = 450 nm, τ = 6.3 ps) in methanol.
- Wang, Jin,Burdzinski, Gotard,Gustafson, Terry L.,Platz, Matthew S.
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p. 6221 - 6228
(2007/10/03)
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- PROCESS
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A process for the alkoxyalkylation of an unsubstituted aromatic substrate or a substituted aromatic substrate, said substitution being via a carbon-carbon bond, said process comprising reacting the aromatic substrate with a dialkoxyalkane in the presence of a catalyst.
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Page/Page column 15-16
(2008/06/13)
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- SYNTHESIS OF PHENYL SUBSTITUTED CYCLOHEXA-1,4-DIENES AND CYCLOHEXA-2,5-DIENONES BY ANODIC METHOXYLATION OF ALKYLBIPHENYLS
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The anodic methoxylation of a series of alkylbiphenyls (2-, 3-, 4-methylbiphenyl, 3,3'-, 4,4'-dimethylbiphenyl, 4-ethylbiphenyl and 4,4'-di-tert-butylbiphenyl) carried out under constant current intensity afforded, in a process of two electrons, a number of cis/trans cyclohexa-1,4-dienes and, in a process of four electrons, a number of cyclohexa-2,5-dienones after acidic hydrolysis of the corresponding cyclohexa-1,4-diene ketals.In some cases, side-chain substitution products were also obtained.Probable mechanisms are proposed.
- Barba, Isidoro,Chinchilla, Rafael,Gomez, Cecilia
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p. 7813 - 7822
(2007/10/02)
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