60594-22-1Relevant articles and documents
A further step to sustainable palladium catalyzed oxidation: Allylic oxidation of alkenes in green solvents
dos Santos Costa, Maíra,de Camargo Faria, Amanda,Mota, Rayssa L.V.,Gusevskaya, Elena V.
, (2021/09/14)
The palladium catalyzed oxidation of alkenes with molecular oxygen is a synthetically important reaction which employs palladium catalysts in solution; therefore, a solvent plays a critical role for the process. In this study, we have tested several green solvents as a reaction medium for the allylic oxidation of a series of alkenes. Dimethylcarbonate, methyl isobutyl ketone, and propylene carbonate, solvents with impressive sustainability ranks and very scarcely exploited in palladium catalyzed oxidations, were proved to be excellent alternatives for the solvents conventionally employed in these processes, such as acetic acid. Palladium acetate alone or in the combination with p-benzoquinone efficiently operates as the catalyst for the oxidation of alkenes by dioxygen under 5–10 atm. For most substrates, the systems in green solvents showed better selectivity for allylic oxidation products as compared to pure acetic acid; moreover, the reactions in propylene carbonate solutions occurred even faster than in acetic acid.
PROCESS FOR PREPARING CARYOPHYLLENE OXIDE
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Paragraph 0020; 0059-0061, (2021/12/29)
The present invention relates to a method for oxidizing beta-caryophyllene with oxygen, in particular atmospheric oxygen, which avoids the use of catalysts, enzymes and solvents. Furthermore, the present invention provides a mixture comprising certain caryophyllene oxides as well as their use as a flavor and/or fragrance. The present invention also relates to products and semi-finished products comprising the mixture according to the invention.
Electron transfer-initiated epoxidation and isomerization chain reactions of β-caryophyllene
Steenackers, Bart,Campagnol, Nicol,Fransaer, Jan,Hermans, Ive,De Vos, Dirk
, p. 2146 - 2156 (2015/01/30)
The abundant sesquiterpene b-caryophyllene can be epoxidized by molecular oxygen in the absence of any catalyst. In polar aprotic solvents, the reaction proceeds smoothly with epoxide selectivities exceeding 70%. A mechanistic study has been performed and the possible involvement of free radical, spin inversion, and electron transfer mechanisms is evaluated using experimental and computational methods. The experimental data-including a detailed reaction product analysis, studies on reaction parameters, solvent effects, additives and an electrochemical investigation-all support that the spontaneous epoxidation of b-caryophyllene constitutes a rare case of unsensitized electron transfer from an olefin to triplet oxygen under mild conditions (80 8C, 1 bar O2). As initiation of the oxygenation reaction, the formation of a caryophyllene-derived radical cation via electron transfer is proposed. This radical cation reacts with triplet oxygen to a dioxetane via a chain mechanism with chain lengths exceeding 100 under optimized conditions. The dioxetane then acts as an in situ-formed epoxidizing agent. Under nitrogen atmosphere, the presence of a one-electron acceptor leads to the selective isomerization of b -caryophyllene to isocaryophyllene. Observations indicate that this isomerization reaction is a novel and elegant synthetic pathway to isocaryophyllene.
