84174-33-4Relevant academic research and scientific papers
Tetraphenylphosphonium Tetrafluoroborate/1,1,1,3,3,3-Hexafluoroisopropanol (Ph4PBF4/HFIP) Effecting Epoxide-Initiated Cation-Olefin Polycyclizations
Tian, Yan,Xu, Xin,Zhang, Lin,Qu, Jin
, p. 268 - 271 (2016/02/03)
The use of an excess amount of tetraphenylphosphonium tetrafluoroborate in 1,1,1,3,3,3-hexafluoroisopropanol, which can stabilize the intermediate cation in the reaction, efficiently promoted epoxide-initiated cation-olefin polycyclization reactions with broad functional group tolerance and water and oxygen tolerance.
Regioselective ring-opening of epoxides with ortho-lithioanisoles catalyzed by BF3·OEt2
Ertürk, Erkan,Tezeren, Mustafa A.,Atalar, Taner,Tilki, Tahir
experimental part, p. 6463 - 6471 (2012/08/27)
It is presented that a number of o-2-hydroxyalkylanisoles could be efficiently synthesized through the regioselective ring-opening reaction of epoxides with o-lithioanisoles in the presence of BF3·OEt 2 Lewis-acid catalyst. Sterically demanding o-lithioanisoles had to be generated by exploiting the combination of nBuLi and a catalytic amount of TMEDA (0.20 equiv) in Et2O as the lithiator whereas 'normal' anisole could be lithiated at ortho-position by treatment with nBuLi in THF as usual. Surprisingly, the availability of THF and a catalytic amount of TMEDA (0.20 equiv) in the reaction mixture was found to enhance the reaction yields dramatically. A complex aggregate formation by the co-operative ligation of THF and TMEDA to ortho-lithioanisole(s) was proposed to rationalize the high reactivity achieved in the ring-opening reaction of epoxides.
1,2-Diarylethanols by alternative regioselective reductive ring-opening of 2,3-diaryloxiranes
Blasio, Nadia Di,Lopardo, Maria Teresa,Lupattelli, Paolo
supporting information; experimental part, p. 938 - 944 (2009/07/19)
Non-symmetrical ￡rans-2,3-diaryloxiranes have been regioselectively opened by catalytic hydrogenation over Pd/C, NaBH4/Pd and [Cp 2TiCl]/H2O. Although in the catalytic hydrogenation reactions the epoxides were mainly opened at the β-carbon with respect to the substituted aryl ring in all cases, with the [Cp2TiCl]/H 2O system the regioselectivity was affected by the electronic properties of the aryl residues, the epoxides being opened on the carbon bearing the most electron-releasing or the least electron-withdrawing group. With the NaBH4/Pd system different regioisomers were obtained depending on the substituents. Starting from enantioenriched epoxides, no loss of optical purity was observed in the alcohols formed.
Molybdenum-catalyzed aromatic substitution with olefins and alcohols
Shimizu, Isao,Khien, Kuok Meng,Nagatomo, Miki,Nakajima, Takayuki,Yamamoto, Akio
, p. 851 - 852 (2007/10/03)
A new type of electrophilic aromatic substitution without using organic halides has been realized by using Mo(CO)6 catalyst.
Generation and Reactions of 2-Alkoxydiphenylcarbenes in Fluid Solution and Rigid Matrices
Tomioka, Hideo,Nakanishi, Keisaku,Izawa, Yasuji
, p. 465 - 470 (2007/10/02)
Irradiation of 2-alkoxydiphenyldiazomethanes 1 in cyclohexane at room temperature produced 3-phenyldihydrobenzofurans 3 presumably as a result of intramolecular C-H insertion of 2-alkoxydiphenylcarbenes 2.Irradiation of compounds 1 in cyclohexane matrix at -196 deg C gave intermolecular C-H insertion products 4 at the expense of benzofurans 3.The formation of products 4 is explicable in terms of H-atom tunnelling to the triplet state of carbenes 2, followed by coupling of the resulting radical pairs.Product ratios 3:4 were somewhat sensitive to the bulk of the alkoxy group at the 2-position.This can be explained in terms of the matrix effect on the relative population of the rotational isomers of the carbene 2.Irradiation of compounds 1 in methanol at room temperature afforded O-H insertion products 5 almost exclusively, whereas irradiation in methanol matrix at -196 deg C gave C-H insertion products 6 along with other products 3 and 5.
A Comparison of Some Friedel-Crafts and Grignard Reactions of Optically Active Phenyloxirane
Taylor, Stephen K.,Haberkamp, William C.,Brooks, Dee W.,Whittern, David N.
, p. 1745 - 1747 (2007/10/02)
The Friedel-Crafts reactions of optically active phenyloxirane with toluene and anisole were examined for stereospecifity.The enantiomeric ratios of the diarylethanol products were determined and compared to those of the same products obtained from the reaction of p-tolyl and p-methoxyphenyl Grignard reagents with optically active phenyloxirane.The p-tolyl Grignard and Friedel-Crafts products gave similar enantiomeric ratios (approximately 64:36 and 60:40, respectively).However, in the p-methoxyphenyl products from the Grignard and Friedel-Crafts reactions, different enantiomers predominated (ratios 33:67 and 62:38, respectively).
