16845-02-6Relevant articles and documents
Benzylic Phosphates in Friedel-Crafts Reactions with Activated and Unactivated Arenes: Access to Polyarylated Alkanes
Pallikonda, Gangaram,Chakravarty, Manab
, p. 2135 - 2142 (2016/03/15)
Easily reachable electron-poor/rich primary and secondary benzylic phosphates are suitably used as substrates for Friedel-Crafts benzylation reactions with only 1.2 equiv activated/deactivated arenes (no additional solvent) to access structurally and electronically diverse polyarylated alkanes with excellent yields and selectivities at room temperature. Specifically, diversely substituted di/triarylmethanes are generated within 2-30 min using this approach. A wide number of electron-poor polyarylated alkanes are easily accomplished through this route by just tuning the phosphates.
Di- and triarylmethylium ions as probes for the ambident reactivities of carbanions derived from 5-benzylated Meldrum's acid
Chen, Xi,Tan, Yue,Berionni, Guillaume,Ofial, Armin R.,Mayr, Herbert
supporting information, p. 11069 - 11077 (2014/10/15)
The kinetics of the reactions of carbocations with carbanions 1 derived from 5-benzyl-substituted Meldrum's acids 1-H (Meldrum's acid=2,2-dimethyl-1,3- dioxane-4,6-dione) were investigated by UV/Vis spectroscopic methods. Benzhydryl cations Ar2CH+ added exclusively to C-5 of the Meldrum's acid moiety. As the second-order rate constants (kC) of these reactions in DMSO followed the linear free-energy relationship lg k=s N(N+E), the nucleophile-specific reactivity parameters N and s N for the carbanions 1 could be determined. In contrast, trityl cations Ar3C+ reacted differently. While tritylium ions of low electrophilicity (E-2) reacted with 1 through rate-determining β-hydride abstraction, more Lewis acidic tritylium ions initially reacted at the carbonyl oxygen of 1 to form trityl enolates, which subsequently reionized and eventually yielded triarylmethanes and 5-benzylidene Meldrum's acids by hydride transfer.
Towards a comprehensive hydride donor ability scale
Horn, Markus,Schappele, Ludwig H.,Lang-Wittkowski, Gabriele,Mayr, Herbert,Ofial, Armin R.
supporting information, p. 249 - 263 (2013/02/25)
Rates of hydride transfer from several hydride donors to benzhydrylium ions have been measured at 20 °C and used for the determination of empirical nucleophilicity parameters N and sN according to the linear free energy relationship log k20 °C=sN(N+E). Comparison of the rate constants of hydride abstraction by tritylium ions with those calculated from the reactivity parameters sN, N, and E showed fair agreement. Therefore, it was possible to convert the large number of literature data on hydride abstraction by tritylium ions into N and sN parameters for the corresponding hydride donors, and construct a reactivity scale for hydride donors covering more than 20 orders of magnitude.
Hydride-donor abilities of 1,4-dihydropyridines: A comparison with π nucleophiles and borohydride anions
Richter, Dorothea,Mayr, Herbert
supporting information; experimental part, p. 1958 - 1961 (2009/07/25)
(Chemical Equation Presented) How are dihydropyridines like indoles? Both groups of compounds have similar nucleophilicity parameters N and are therefore suitable substrates for iminium-catalyzed reactions of α,β- unsaturated aldehydes. The N parameters of 1,4-dihydropyridines were derived from the rates of hydride transfer reactions to benzhydrylium ions (see scheme).
Methylium ions with OPV chains - New NIR dyes
Meier, Herbert,Kim, Soungkyoo
, p. 1163 - 1167 (2007/10/03)
Carbinols, which contain three OPV chains, were generated in convergent syntheses. The extension of the conjugation leads to a bathochromic effect that shifts the absorption from the UV into the visible region. The carbinol series has a convergence limit
Photolysis of 1,1,1,2-Tetraarylalkanes in the Presence of 1,4-Dicyanobenzene. A Photochemical C-C Bond Cleavage Reaction of Radical Cations in Solution
Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
, p. 1831 - 1840 (2007/10/02)
Irradiation of acetonitrile-methanol (1:1) solutions of 1,1,1,2-tetraarylalkanes or 1,1,1-triphenyl-2-methoxyethane containing 1,4-dicyanobenzene led to the formation of triarylmethane and triarylmethyl methyl ethers in good yields.This C-C bond cleavage reaction is thought to proceed via a radical cation intermediate.
