60594-23-2Relevant articles and documents
An effective procedure for the synthesis of acid-sensitive epoxides: Use of 1-methylimidazole as the additive on methyltrioxorhenium-catalyzed epoxidation of alkenes with hydrogen peroxide
Yamazaki, Shigekazu
, p. 2377 - 2385 (2010)
An effective method for suppression of ring opening and rearrangement of acid-sensitive epoxides during methyltrioxorhenium(MTO)-catalyzed epoxidation of alkenes with H2O2 by using 1-methylimidazole as a co-additive has been found. The combined use of 3-methylpyrazole and 1-methylimidazole as the additives has been found to be an effective procedure that affords excellent yields of acid-sensitive epoxides for MTO-catalyzed epoxidation.
An ultrathin amino-acid based copper(II) coordination polymer nanosheet for efficient epoxidation of β-caryophyllene
Fu, Zaihui,Huang, Hongmei,Mao, Liqiu,Mao, Wensheng,Shi, Lihan,Xiao, Yi,Yin, Dulin,Yu, Ningya,Zhang, Li,Zhao, Yaqian
, (2021/07/26)
Natural amino acids are important building blocks for the construction of intriguing coordination polymers (CPs) because of their abundance, inexpensiveness and environmental benignness. Herein, two copper(II) CPs, namely, 2D CuIle-e nanosheet (e: ethanol) and 1D CuIle-m nanoshuttle (m: methanol), were fabricated from L-isoleucine (Ile) and well characterized with single-crystal x-ray diffraction, XPS spectra, TEM and AFM, etc. More importantly, two novel and stable catalytic nanosystems, i.e. CuIle-e/acetone/TBHP (tert-butyl hydroperoxide) and CuIle-e/THF/O2/TBHP, were thus conveniently built by using ultrathin 2D CuIle-e nanosheet (~ 2.3 nm) in suitable aprotic solvents. Under mild conditions, complete conversion of β-caryophyllene and good yields (86.1% or 87.2%) for β-caryophyllene epoxide were gained via CuIle-e/acetone/TBHP or CuIle-e/THF/O2 (1 atm)/TBHP (10.0 mol%), respectively. Notably, ultrathin CuIle-e nanosheet showed fairly satisfactory stability, which may open a unique window for the facile fabrication of new amino-acid based CP nanosystems with outstanding catalytic performances in actual applications.
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.
