35907-10-9Relevant articles and documents
Heteropoly acid catalysts for the synthesis of fragrance compounds from biorenewables: Isomerization of limonene oxide
Costa, Vinicius V.,Da Silva Rocha, Kelly A.,Kozhevnikov, Ivan V.,Kozhevnikova, Elena F.,Gusevskaya, Elena V.
, p. 244 - 250 (2013/04/10)
The liquid-phase isomerization of limonene oxide was studied in the presence of heteropoly acid catalysts in aprotic solvents in homogeneous and heterogeneous systems. Among the catalysts were bulk and silica-supported tungstophosphoric acid H3PW12O40 and its acidic Cs salt Cs0.5H0.5PW12O40 (CsPW). The reaction gave dihydrocarvone, a valuable fragrance intermediate, as the main product with turnover numbers of up to 8000. The nature of the solvent had a strong effect on reaction rate and selectivity. CsPW (0.1 mol%) was found to be a highly efficient and truly heterogeneous catalyst for this reaction, providing 82% yield of dihydrocarvone in 1,4-dioxane as a solvent under ambient conditions. This simple catalytic method represents economically attractive route to industrially important compounds starting from bio-renewable substrates easily available from essential oils. The Royal Society of Chemistry 2013.
Mixed disproportionation versus radical trapping in titanocene(III)-promoted epoxide openings
Justicia, José,Jiménez, Tania,Morcillo, Sara P.,Cuerva, Juan M.,Oltra, J. Enrique
experimental part, p. 10837 - 10841 (2010/02/28)
The formation of either deoxygenation products or allylic alcohols from epoxides is observed when these substrates are treated with Cp2TiCl under anhydrous conditions. It seems that processes via trisubstituted radicals give allylic alcohols whereas processes via disubstituted radicals may give deoxygenation products or allylic alcohols depending on the structure of the original epoxide. This method allows a controlled access to these functional groups, providing a useful tool in organic synthesis. A mechanistic discussion for these transformations is reported.
Pd-containing catalytic system for oxidative acetoxylation of alkenes
Romanenko,Tormyshev,Shteingarts
, p. 1549 - 1562 (2007/10/03)
Four-substituted cyclohexenes were used as examples for revealing the substituent effect on composition of products obtained by oxidative acetoxylation of alkenes catalyzed with Pd(II) acetate. The distribution of products is rationalized on assumption of relative stability of allylic anions and steric strains in (π-allyl)palladium intermediates. Stereoselective yield of trans-substituted endo-acetates is due to stabilizing effect of lower unoccupied orbital of the forming C-OAc bond and occupied orbitals of pseudoaxial C-H bonds at the cycle in the transition states. The substrates capable of this reaction are limited to alkenes with insignificant steric shielding of the double bond. The study of the influence on the process of the characteristics of oxidant used in the catalytic system revealed that the most significant difference is observed between catalysts prepared as homogeneous oxidative systems and those containing heterogeneous oxidant MnO2 or TiO2 as additive. 1998 MAHK "Hayka/Interperiodica".
