4132-49-4Relevant articles and documents
Hydroperoxide method for the synthesis of p-tert-butylphenol
Frolov, A. S.,Korshunova, A. I.,Koshel’, G. N.,Kurganova, E. A.,Yarkina, E. M.
, p. 1951 - 1956 (2021/11/05)
The results of studies related to the development of a highly selective three-stage method for the synthesis of p-tert-butylphenol along with acetone are presented. The alkylation of isopropylbenzene with tert-butyl alcohol in the presence of concentrated sulfuric acid makes it possible to obtain only the para-isomer of tert-butylcumene. For the liquid-phase aerobic oxidation of p-tert-butylcumene in the presence of the phthalimide catalysts, the hydrocarbon conversion reaches 45% with a selectivity of hydroperoxide formation of 90–95%. The process of acid decomposition of p-tert-butylcumene hydroperoxide to p-tert-butylphenol and acetone was studied. Conditions providing the production of p-tert-butylphenol in a yield of 90% were found.
Facile Hydrogenolysis of C(sp3)–C(sp3) σ Bonds
Fillion, Eric,Beaton, Eric,Nguyen, Yen,Wilsily, Ashraf,Bondarenko, Ganna,Jacq, Jér?me
supporting information, p. 3422 - 3434 (2016/11/13)
The modification of benzylic quaternary, tertiary, and secondary carbon centers through palladium-catalyzed hydrogenolysis of C(sp3)–C(sp3) σ bonds is presented. When benzyl Meldrum's acid derivatives bearing quaternary benzylic centers are treated under mild hydrogenolysis conditions – palladium on carbon and atmospheric pressure of hydrogen – aromatics substituted with tertiary benzylic centers and Meldrum's acid are obtained with good to excellent yield. Analogously, substrates containing tertiary or secondary benzylic centers yield aromatics substituted with secondary benzylic centers or toluene derivatives, respectively. Furthermore, this strategy is used for the high yielding synthesis of diarylmethanes. The scope of the reductive dealkylation reaction is explored and the limitations with respect to steric and electronic factors are determined. A mechanistic analysis of the reaction is described that consisted of deuterium labelling experiments and hydrogenolysis of enantioenriched derivatives. The investigation shows that the C(sp3)–C(sp3) σ bond-cleaving events occur through a hybrid SN1/SN2 mechanism, in which the palladium center displaces a carbon-based leaving group, namely Meldrum's acid, with inversion of configuration, followed by reductive elimination of palladium to furnish a C?H bond. (Figure presented.).
Efficient Synthesis and Resolution of trans-2-(1-Aryl-1-methylethyl)cyclohexanols; Practical Alternatives to 8-Phenylmenthol
Comins, Daniel L.,Salvador James M.
, p. 4656 - 4661 (2007/10/02)
A short synthesis and resolution of effective chiral auxiliaries of the 8-arylmenthol-type achieved using inexpensive materials, a recyclable lipase, and easily applied procedures that are amenable to large-scale preparation.A variety of isopropylarenes were α-metalated with n-butylithium/potassium tert-pentoxide and treated with cyclohexene oxide to provide racemic trans-2-(1-aryl-1-methylethyl)cyclohexanols 6a-f in fair to high yield.Candida rugosa lipase and lauric acid were used to resolve these racemic alcohols by converting the (-)-enantiomer to its laurateester.The enzymatic resolutions were carried out at 40 deg C and were faster in cyclohexane than in hexanes.The synthesis and resolution of racemic trans-2-(1-methyl-1-phenylethyl)cyclohexanol (6a) were performed on a 1 mol scale in 68 percent overall yield, requiring three steps for (+)-6a and five steps for (-)-6a.
