5944-41-2Relevant academic research and scientific papers
Access to "friedel-Crafts-Restricted" tert -alkyl aromatics by activation/methylation of tertiary benzylic alcohols
Hartsel, Joshua A.,Craft, Derek T.,Chen, Qiao-Hong,Ma, Ming,Carlier, Paul R.
scheme or table, p. 3127 - 3133 (2012/05/20)
Herein we describe a two-step protocol to prepare m-tert-alkylbenzenes. The appropriate tertiary benzylic alcohols are activated with SOCl2 or concentrated HCl and then treated with trimethylaluminum, affording the desired products in 68-97% yields (22 examples). This reaction sequence is successful in the presence of a variety of functional groups, including acid-sensitive and Lewis-basic groups. In addition to t-Bu groups, 1,1-dimethylpropyl and 1-ethyl-1-methylpropyl groups can also be installed using this method.
Ligand coupling reactions of 2-pyridyl, 4-pyridyl and 2-pyrimidyl sulfoxides with grignard reagents
Oae, Shigeru,Takeda, Takeshi,Uenishi, Junichi,Wakabayashi, Shoji
, p. 179 - 182 (2007/10/03)
The ligand coupling reaction was extended to 3-and 4-pyridyl sulfoxides as well as the 2-pyrimidyl moiety with Grignard reagents. It was found that both 4-pyridyl and 2-pyrimidyl sulfoxides nicely underwent the ligand coupling reactions, but 3-pyridyl sulfoxide underwent ligand exchange.
tert-Butylation of Quinolinium Cations and Quinoline N-Oxides by tert-Butylmercury Halides
Russell, Glen A.,Wang, Lijuan,Yao, Ching-Fa
, p. 5390 - 5395 (2007/10/02)
In the presence of t-BuHgCl/KI the radical cations formed by the addition of tert-butyl radicals to C-2 of the quinolinium cation react in Me2SO by proton loss followed by one-electron oxidation (1a, R=H, Me, Cl).For the N-methyl, or N-methoxyquinolinium cations proton loss is not observed and the radical cations react by one-electron reduction (1b, R=Me, Cl; 1c, R=Me).With quinoline N-oxide and its 4-substituted derivatives the C-2 adduct radicals (1d, R=H, Me, Cl) are deprotonated by DABCO to yield after one-electron oxidation the 2-tert-butylquinoline N-oxides.The adduct radical cations formed by t-Bu. addition at the C-4 quinolinium ions 2 seldom lose the C-4 proton but react by reduction, hydration, or in the case of 2-chloroquinoline N-oxide, dimerization.The loss of the proton from the 2-adducts 1 but not from the 4-adducts 2 seems to be stereoelectronic in origin.With N-methylquinolinium cation the addition of t-Bu. occurs selectively (>90percent) at C-4 in contrast to the low selectivity observed in addition to quinolinium ion itself.However, with N-methoxyquinolinium perchlorate the major reaction products (70-90percent) result from the addition of t-Bu. at C-2.
tert-butylation of pyridines, quinolines, and isoquinolines by tert-butylmercury halides
Russell, Glen A.,Rajaratnam, Rajine,Wang, Lijuan,Shi, Bing Zhi,Kim, Byeong Hyu,Yao, Ching Fa
, p. 10596 - 10604 (2007/10/02)
Photolysis of tert-butylmercury halides with pyridinium or quinolinium salts leads to alkylation via the intermediacy of adduct radical cations. With simple pyridines or the 2-adducts from quinolines, the radical cations readily lose a proton to form a substituted pyridinyl radical which is easily oxidized by the alkylmercury halide. Addition of t-Bu? at the 4-position of the quinolinium ions, the 1-position of the isoquinolinium ions, or the 9-position of the acridinium ions, yields in the presence of KI the dihydro derivatives formed via electron transfer to the adduct '? radical cation from I- or its ate-complex with the tert-butylmercury halide. A similar reductive alkylation is observed for the radical cations formed by the addition of t-Bu? to the β-position of the 4-vinylpyridinium ion or to the N-methylated cations derived from pyridine-3,4-dicarboximide, acridine, quinaldine, or isoquinoline. Competition between substitutive (oxidative) and additive (reductive) alkylation reflects the ease of proton loss from the intermediate adduct radical cation. Because of reversibility in adduct formation and variable rates of deprotonation of the adducts, yields of substitutive alkylation products are often not a true measure of the selectivity in the initial radical addition step. 4-tert-Butyl-1,4-dihydro-2-methylquinoline can be isolated from the photolysis of quinaldine with t-BuHgCl in the presence of KI/PTSA, methylated at C-3 by methyl iodide during the tert-butylation reaction, reduced by NaBH4 upon workup, or oxidized to the quinoline at long reaction times. 4-tert-Butyl-1,4-dihydroquinoline reacts rapidly in the presence of PTSA and t-BuHgCl to form 2,4-di-tert-butyl-1,2,3,4-tetrahydroquinoline while 4-/er/-butyl-2-chloro1,4-dihydroquinoline is readily hydrolyzed to form the amide. Although 1 -tert-butyl-1,2-dihydro-3-methylisoquinoline is isolable, 1 -tert-butyl-1,2-dihydroisoquinoline reacts via the iminium ion to form 1,3-di-tert-butyltetrahydroisoquinoline and the de-tert-butylated product 3-tert-butyl-3,4-dihydroisoquinoline. De-tert-butylation with aromatization is also observed upon photolysis of 4-tert-butyl-3,4-dihydro-2,3-dimethylquinoline with t-BuHgCl.
OCCURRENCE OF LIGAND COUPLING IN THE REACTIONS OF VARIOUS SULFOXIDES WITH GRIGNARD REAGENTS
Kawai, Tsutomu,Kodera, Yoichi,Furukawa, Naomichi,Oae, Shigeru,Ishida, Masahiro,et al.
, p. 139 - 148 (2007/10/02)
Ligand coupling reactions take place not only between benzyl and 2-pyridyl groups and two 2-pyridyl groups in the treatment of benzyl, alkyl and aryl 2-pyridyl sulfoxides with Grignard reagents, but also between such groups as p-benzenesulfonylphenyl, 4-pyridyl, 2-quinolyl and 2-pyrimidyl, and the benzyl group.There are cases in which ligand exchange precedes ligand coupling, especially with 2-heteroaryl groups.In addition, even some alkyl groups were found to couple with the 2-pyridyl group.The ease of coupling seems to be associated with the electronegativity of the coupling carbon atom of the ligand, when one compares the 13C NMR chemical shifts.
Alkylation of Pyridine in Free Radical Chain Reactions Utilizing Alkylmercurials
Russell, Glen A.,Guo, Deliang,Khanna, Rajive K.
, p. 3423 - 3425 (2007/10/02)
Pyridines or N,N,N',N'-tetramethyl-p-phenylenediamine will undergo a photostimulated free radical chain reaction with alkylmercury halides or carboxylates, yielding ring alkylated substitution products.Alkene mercuration products (R1CH(Y)CH(R2)HgX with Y=HO, RO, CH3CONH; X=Cl, CH3CO2, CF3CO2) can be used without isolation for the alkylation reaction
