The same oxidation at higher temperature 60 C produced the a-brominated ester, octyl 2-bromooctanoate, which is considered to be formed through an alkenyl alkyl ether as the intermediate.
A variety of terpenes was oxidized to the corresponding monoepoxides or diepoxides in good yields under mild conditions. For example, limonene 1 was converted into limonene oxide 1a in which the cyclohexene double bond was selectively epoxidized in almost quantitative yield. The oxidation of g-terpinene 2 with 2. In terpenes bearing electron-withdrawing groups such as neryl acetate 3 , geranyl acetate 4 , citral 5 , and geranyl nitrile 6 , the double bonds remote from their substituents were epoxidized in preference to the others. The epoxidation of linalool 9 by the present catalyst-oxidant system produced the cyclic products, hydroxy furan 9a and hydroxy pyran 9b, rather than epoxide.
Tert-Butyl alcohol was successfully employed as the solvent by treating a hydrogen peroxide solution of tert-butyl alcohol with MgSO4 prior to use. The regioselectivities in the epoxidation of monoterpenes can be favorably explained by electron densities of the double bonds which were estimated using the CAChe system. When the reaction was carried out using tert-butyl alcohol as a solvent, approximately a regioisomeric mixture of a-hydroxy ketones was obtained along with a small amount of a-tert-butoxy ketone.
Oxidation of internal alkynes such as 4-octyne by the PCWP-H2O2 system under phase-transfer conditions using chloroform produced a,b-epoxy ketones in good yields. The same reaction in a mixed solvent of ethanol and chloroform gave a,b-unsaturated ketones rather than a,b-epoxy ketones. Iridium-catalyzed coupling reactions. Nitrasation of Cyclohexane Catalyzed by N-Hydroxyputhalimide.
Synthesis of quinolines from amino alcohol and ketones catalyzed by [IrCl cod ]2 or IrCl3 under solvent-free conditions. One-pot synthesis of phenol and cyclohexanone from cyclohexylbenzene catalyzed by N-hydroxyphthalimide NHPI. Synthesis of a-hydroxy-c-butyrolactones from acrylates and 1,3-dioxolanes using N-hydroxyphthalimide NHPI as a key catalyst.
Development of an efficient method for preparation of 1,3,5-trihydroxyisocyanuric acid THICA and its use as aerobic oxidation catalyst.
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Oxidation of substituted toluenes with molecular oxygen in the presence of N,N ',N ''-trihydroxyisocyanuric acid as a key catalyst. Addition of aldehydes and their equivalents to electron-deficient alkenes using N-hydroxyphthalimide NHPI as a polarity-reversal catalyst. The first hydroxysilylation of alkenes with triethylsilane under dioxygen catalyzed by N-hydroxyphthalimide. Oxidation of nitrotoluenes with air using N-hydroxyphthalimide analogues as key catalysts. Head-to-tail dimerization of acrylates catalyzed by iridium complexes.
Alkane Nitration Assisted by N-Hydroxyphthalimide. Synthesis of enol and vinyl esters catalyzed by an iridium complex. Aerobic oxidation of ethane to acetic acid catalyzed by N,N'-dihydroxypyromellitimide combined with Co species. Discovery of a carbon radical producing catalyst and its application to organic synthesis. First Ritter-type reaction of alkylbenzenes using N-hydroxyphthalimide as a key catalyst. Remarkable effect of nitrogen dioxide for N-hydroxyphthalimide-catalyzed aerobic oxidation of methylquinolines.
N-Hydroxyphthalimide - WikiVisually
The radical-chain addition of aldehydes to alkenes by the use of N-hydroxyphthalimide NHPI as a polarity-reversal catalyst. N-Hydroxyphthalimide-catalyzed radical addition of 1,3-dioxolanes and molecular oxygen to alkenes under ambient conditions: a new route to b-oxycarbonyl compounds. Catalytic radical addition of ketones to alkenes by a metal-dioxygen redox system. Synthesis of 1,3-oxazolidines from imines and epoxides catalyzed by samarium compounds.
Iridium-catalyzed aziridination of aliphatic aldehyde, aliphatic amine and ethyl diazoacetate. Meerwein-Ponndorf-Verley-type reductive acetylation of carbonyl compounds to acetates by lanthanide complexes in the presence of isopropenyl acetate. Epoxidation of alkenes with H2O2 generated in situ from alcohols and molecular oxygen using N-hydroxyphthalimide and hexafluoroacetone as catalyst.
In addition, selective generation of esters using porous catalysts has been elusive. This reaction is catalyzed by a Li ion promoted mesoporous manganese oxide meso-Mn2O3 under mild conditions with no precious metals, a reusable heterogeneous catalyst, and easy isolation. This process is very attractive for the oxidation of allyl ethers.
We report on the catalytic activity, selectivity, and scope of the reaction. In the best cases presented, almost complete conversion of allyl ether with near complete chemo-selectivity towards acrylate ester derivatives is observed. Based on results from controlled experiments, we propose a possible reaction mechanism for the case in which N-hydroxyphthalimide NHPI is used in combination with trichloroacetonitrile CCl3CN.
Correspondence and requests for materials should be addressed to P.
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Acrylates are key 2. The industrial source of acrylics Moreover, reaction under NHPI—air with no CCl3CN displayed a and acrylates is propylene that is produced as either the by- rate constant of 0.
Propane or propylene can be subse- entry 2 and 3. These superiority. These studies helped evaluate the depending on the reaction condition employed Typically these importance of reaction parameters.
Innovation of Hydrocarbon Oxidation with Molecular Oxygen and Related Reactions
Further characteriza- C—H oxidation However, these methodologies primarily focus tion was done with X-ray powder diffraction and BET surface on cyclic unsaturated molecules. Crystalline manganese oxide area measurements Supplementary Fig.
Various reactants and based materials e. The substrate scope and limitations were then silanes22, anilines to azobenzenes23, and dehydrogenative oxida- explored using structurally different ethers, with each possessing tion reaction of alkanes Under optimized reaction condi- These mixed valent manganese oxide materials have numerous tions, diallyl ether and cyclic dihydrofuran Table 1, entry 1 and structural forms with high thermal stability On the other are responsible for their catalytic performance21, These lattice hand, allyl acetate and allyl glycidyl ether Table 1, entry 2 and 4 oxygens act as basic sites for H abstraction during the reaction.
Moreover, for allyl phenyl ether Table 1, entry 5. Basicity increases allyl ether than that of phenyl allyl ether B.
Catalysis of Organic Reactions (Chemical Industries)
This resulted in better positive ions. We therefore introduced these types of ions in the stability and poorer reactivity of the phenyl allyl ether than the allylic C—H oxidation reactions. These mesoporous manganese allyl ether. To investigate the reason for selective formation of oxide materials, developed by an inverse-micelle method, were monoesters over the anhydride, density functional theory DFT selected for their comparatively high surface areas compared with calculations were conducted, using the CBS—QB3 basis set.
DFT traditional mesoporous transition metal oxides A smaller increase in low-temperature process with lithium ion impregnated meso- bond dissociation energy was observed when comparing reactants porous manganese oxides as heterogeneous catalysts. An advan- and products in Table 1, entry 3. Perhaps the cyclic nature of the tage of these catalysts is that manganese oxides are abundant and substrate binding to the catalyst surface further limited the oxi- inexpensive materials. Such studies suggest for oxidation with a calculated BDE of A stituted allyl ethers Table 1, entry 6 and 7.
To determine if the observed catalysis is reaction. Aliquots were collected successively after each hour and were analyzed with GC- Results MS to track the progress of the reaction. No further improvement Reaction conditions. Reaction absence of a catalyst. Numbers in parenthesis are the isolated yields. This suggest the formation of a superoxomanganese IV and methanol. In for 30 min under air to remove any adsorbed substrates. As both cases, a series of steps contributed to the formation of evident from Supplementary Fig.
These are considered to be MnIII , caused by the strong coordination of different radicals very reactive and are expected to deprotonate the NHPI molecule with the metal centers. Therefore, our catalyst can be considered to form a PINO radical and a MnIV—hydrogen peroxide 3 as truly heterogeneous, stable, and moderately reusable. The latter went through further rearrangements with the paramagnetic resonance EPR measurements A fourfold decrease in the rate constant i. Moreover, we have independently determined catalytic reaction attractive. Since O2 is highly abundant and extensive optimization of the reaction conditions.
Transiting from Adipic Acid to Bioadipic Acid. 1 ... - ACS Publications
The transformation of catalytic process was interpreted by control experiments that led intermediate 8 to 9, probably resulted in the release of oxygen, to a plausible mechanism. Mechanistic studies invoked the pos- which are the terminal oxidants of the catalytic process Fig. The presence of the CCl3CN pro- action in the oxidation process is still unknown.
Methods Catalysis. In this paper, we have developed a new catalytic approach to the mild Previous work: aerobic partial oxidations of diallyl ether, see Fig. We demonstrate the aerobic oxidation of allyl ethers to corresponding NH3, O2 O acrylate esters using various cation doped mesoporous manganese oxide materials. O2 We initiated the oxidation of allyl ether in air as a model reaction to determine N O meso-Li-Mn2O3 the optimal conditions.
In our early screening attempts, we evaluated the impact of 2 mmol 2 eqv. Interestingly, no trace of the oxidized product was detected until tert-butylhydroperoxide TBHP was Fig. Unsatisfactory conversion of allyl ether, even after using TBHP led us to employ a radical promoter. The high species used in the catalytic reaction, and shows a detailed set of pathways electrophilicity of the CCl3CN most likely promoted the homolytic cleavage of that account for observed products O—O bonds of mCPBA by forming a highly unstable peroxyimidate adduct.
The role of CCl3CN was oxidants. The promising results of solvent optimization led to evaluation of other metal oxide supports. Better accessibility of the labile author upon reasonable request.