- The air-stable carbocation salt [(MeOC6H4)CPh2][BF4] in Lewis acid catalyzed hydrothiolation of alkenes
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Markovnikov hydrothiolation of 1,1-disubstituted and trisubstituted olefins (20 examples) is catalyzed by Lewis acids, including the air-stable trityl-cation salt [(MeOC6H4)CPh2][BF4] 3.
- Mosaferi, Eliar,Ripsman, David,Stephan, Douglas W.
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supporting information
p. 8291 - 8293
(2016/07/06)
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- Stabilities of trityl-protected substrates: The wide mechanistic spectrum of trityl ester hydrolyses
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Ionization rates of para-substituted triphenylmethyl (trityl) acetates, benzoates, and para-nitrobenzoates have been determined in aqueous acetonitrile and aqueous acetone at 25 °C. Conventional and stoppedflow techniques have been used to evaluate rate constants ranging from 1.38 × 10-5 to 2.15 × 102S-1 by conductimetry and photospectrometry methods. The varying stabilities of the differently substituted tritylium ions account for a gradual change of reaction mechanism. Poorly stabilized carbocations are generated slowly by the ionization of their covalent precursors and trapped fast by water. Better stabilized carbocations are generated more rapidly and accumulate, so that ionization and trapping by water can be observed as separate steps in a single experiment. Finally, highly stabilized tritylium ions do not react with water, and only the rates of their formation could be measured. The ionization rate constants correlate linearly with Winstein's ionizing powers Y; the low slopes (0.17 + parameters is excellent for symmetrically substituted tritylium derivatives, deviations for unsymmetrically substituted systems are observed. The failing rate-equilibrium relationship between the rates of ionizations (log kion) and the stabilities of the carbocations in aqueous solution (pKR+) may be explained by the late " development of resonance between a p-amino group and the carbocationic center of the tritylium ion during the ionization process.
- Horn, Markus,Mayr, Herbert
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supporting information; experimental part
p. 7469 - 7477
(2010/09/11)
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- Ion pairing and salt structure in organic salts through diffusion, overhauser, DFT and X-ray methods
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Pulsed gradient spin-echo (PGSE) diffusion characteristics for a) the new [brucinium][X] salts 6a-f [a: X = BF4-; b: X = PF6-; c: X = MeSO3-, d: X = CF3SO3; e: X = BArF - f: X = PtCl3
- Moreno, Aitor,Pregosin, Paul S.,Veiros, Luis F.,Albinati, Alberto,Rizzato, Silvia
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experimental part
p. 6848 - 6862
(2010/03/02)
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- Preparations, X-ray crystal structure determinations, and base strength measurements of substituted tritylamines
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A range of tritylamines TrNRR′, and 4-methoxy-, 4,4′-dimethoxy-, and 4,4′,4″-trimethoxy-substituted analogues, have been prepared from (substituted) trityl chloride, bromide, or tetrafluoroborate with ammonia or with amines HNRR′ where R and R′ are hydrog
- Canle, Moises L.,Clegg, William,Demirtas, Ibrahim,Elsegood, Mark R.J.,Maskill, Howard
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