- An Efficient Ga(OTf)3/Isopropanol Catalytic System for Direct Reduction of Benzylic Alcohols
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This study aims to report the first gallium-catalyzed direct reduction of benzylic alcohols using isopropanol as a reductant. The reaction proceeds via gallium catalyst-assisted hydride transfer of the in situ-generated benzylic isopropyl ether. The method generates only water and acetone as byproducts and thus provides an atom-economic and environmentally friendly approach to the synthesis of di- and triarylmethanes, which are important substructures in various bioactive compounds and functional materials. (Figure presented.).
- Sai, Masahiro
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supporting information
p. 4330 - 4335
(2018/10/15)
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- Aspects of crystal engineering arising from packing behavior of functional mono para-substituted trityl compounds
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Four trityl compounds differing both in the functional group (OH, OMe, NH2) at the specific trityl carbon and a para substituent, being bromine or phenyl at one of the phenyl groups, have been prepared and structurally studied by means of singl
- Knepper, Ingo,Seichter, Wilhelm,Skobridis, Konstantinos,Theodorou, Vassiliki,Weber, Edwin
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p. 6355 - 6369
(2015/08/24)
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- Protolytic defluorination of trifluoromethyl-substituted arenes
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A series of trifluoromethyl-substituted arenes were studied in their reactions with Bronsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMR studies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
- Kethe, Anila,Tracy, Adam F.,Klumpp, Douglas A.
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experimental part
p. 4545 - 4549
(2011/07/29)
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- Base-induced rearrangement of tritylamines to imines: discovery and investigation of the mechanism
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An unexpected compound, the aniline derived benzophenone imine, was isolated when tritylamine was treated with n-BuLi and alkyl halides, during the formation of N-alkyl tritylamines, in the process of preparing primary amines. A nucleophilic attack of the nitrogen anion of tritylamide on the adjacent C-bonded phenyl, either substituted or not, involving a bridging anionic intermediate, is proposed for this base-induced tritylamine rearrangement to produce the corresponding imine. Electron-withdrawing groups in the aromatic ring, favoring the negative charge development, affect the relative migratory tendencies.
- Theodorou, Vassiliki,Skobridis, Konstantinos,Karkatsoulis, Aris
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p. 4284 - 4289
(2007/10/03)
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- Sigmatropic Rearrangements of 1,1-Diarylindenes. Migratory Aptitudes of Aryl Migration in the Ground and Electronically Excited States
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The photochemical and thermal rearrangements of 1,1-diarylindenes to give 2,3-diarylindenes have been investigated.Migratory aptitudes of p-X-phenyl vs. phenyl were determined for X =Br,CN, and OCH3 in the photochemical and thermal migrations.The identities of the products of these rearrangements were established by unambiguous synthesis, and the synthetic work is described.Product ratios were generally determined by NMR techniques, but VPC and isotope dilution were also used in the case of 1-(p-cyanophenyl)-1-phenylindene reactions.The excited-state reactions (direct and triplet sensitized) are highly selective, migration of the substituted phenyl group being favored for all three substituents.The thermal reactions, in contrast, are quite unselective, phenyl migrating almost as readily as the substituted phenyl group in all cases.Quantum yields for the rearrangement in the case of 1,1-diphenylindene and 1-(p-cyanophenyl)-1-phenylindene were 0.80 and 0.4, respectively (direct irradiation), and 0.43 and 0.53 (sensitized reactions).The results of the thermal reactions and results from the literature are discussed in terms of bond-dissociation energies and transition-state-delocalization energies calculated by using the Hueckel theory.Neither approach led to a satisfactory interpretation.The excited-state migrations are consistent with charge-transfer stabilization of the transition state, which can be estimated from oxidation and reduction potentials by using Weller's equation.
- Manning, Carl,McClory, Michael R.,McCullough, John J.
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p. 919 - 930
(2007/10/02)
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