927-07-1Relevant articles and documents
Continuous synthesis of tert-butyl peroxypivalate using a single-channel microreactor equipped with orifices as emulsification units
Illg, Tobias,Hessel, Volker,L?b, Patrick,Schouten, Jaap C.
, p. 392 - 398 (2011)
The two-step synthesis of tert-butyl peroxypivalate is performed in a single-channel microreactor. The first step, the deprotonation of tert-butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial area renewal, needed for ensuring mass transfer between the two immiscible phases. The strong dependence of the reaction performance on the size of the interfacial area is demonstrated by using a setup with 4 orifices (distance of 52 cm), giving a HPLC yield of 71% at a residence time of 8 s and a reaction temperature of 23°C. A further shortening of orifice distances helped to shorten the residence time down to 1.5 s and 0.5 s (using 9 orifices and 3 orifices with a distance of 5 cm). When using these setups, the produced heat could not be removed from the system sufficiently quickly (δT=38 K). The achieved yields (ca. 70% by HPLC) are close to the state of the art (cascaded batch processing) and provide an indication that the tert-butyl peroxypivalate synthesis can be performed at higher temperatures or at least, a more flexible process control can be allowed compared to high-volume batch reactors. Processing at higher reaction temperatures up to 70 °C shows a slight optimum at reaction temperatures between 40°C to 50 , depending on the setup used. Knowing this novel process window as well as the optimum orifice geometry and distance will allow for tailored design of the microreactor. For the processing in the single-channel microreactor setup using 9 orifices (distance of 5 cm) and a reaction temperature of 40 °C a space-time-yield of 420 000 gL-1h-1 was reached which is higher than the space-time-yield for the industrial 3 cascaded batch reactor process (190 gL-1h-1).
Stereoselective Alkylation of Chiral Titanium(IV) Enolates with tert-Butyl Peresters
Pérez-Palau, Marina,Sanosa, Nil,Romea, Pedro,Urpí, Fèlix,López, Rosa,Gómez-Bengoa, Enrique,Font-Bardia, Mercè
supporting information, p. 8852 - 8856 (2021/11/17)
Here, we present a new stereoselective alkylation of titanium(IV) enolates of chiral N-acyl oxazolidinones with tert-butyl peresters from Cα-branched aliphatic carboxylic acids, which proceeds through the decarboxylation of the peresters and the subsequent formation of alkyl radicals to produce the alkylated adducts with an excellent diastereoselectivity. Theoretical calculations account for the observed reactivity and the outstanding stereocontrol. Importantly, the resultant compounds can be easily converted into ligands for asymmetric and catalytic transformations.
Bu4NI-Catalyzed, Radical-Induced Regioselective N-Alkylations and Arylations of Tetrazoles Using Organic Peroxides/Peresters
Ghosh, Subhendu,Mir, Bilal Ahmad,Patel, Bhisma K.,Rajamanickam, Suresh,Sah, Chitranjan,Sethi, Garima,Venkataramani, Sugumar,Yadav, Vinita
, p. 2118 - 2141 (2020/03/13)
Bu4NI-catalyzed regioselective N2-methylation, N2-Alkylation, and N2-Arylation of tetrazoles have been achieved using tert-butyl hydroperoxide (TBHP) as the methyl source, alkyl diacyl peroxides as the primary alkyl source, alkyl peresters as the secondary and tertiary alkyl sources, and aryl diacyl peroxides as the arylating source. These reactions proceed without pre-functionalization of tetrazole and in the absence of any metal catalysts. Here, peroxides serve the dual role of oxidants as well as alkylating or arylating agents. Based on DFT calculations, it was found that spin density, transition-state barriers (kinetic control), and thermodynamic stability of the products (thermodynamic control) play essential roles in the observed regioselectivity during N-Alkylation. This radical-mediated process is amenable to a broad range of substrates and provides products in moderate to good yields.
Decarboxylative Borylation of mCPBA-Activated Aliphatic Acids
Wei, Dian,Liu, Tu-Ming,Zhou, Bo,Han, Bing
supporting information, p. 234 - 238 (2020/01/02)
A decarboxylative borylation of aliphatic acids for the synthesis of a variety of alkylboronates has been developed by mixing m-chloroperoxybenzoic acid (mCPBA)-activated fatty acids with bis(catecholato)diboron in N,N-dimethylformamide (DMF) at room temperature. A radical chain process is involved in the reaction which initiates from the B-B bond homolysis followed by the radical transfer from the boron atom to the carbon atom with subsequent decarboxylation and borylation.
Iron-Catalyzed Vinylic C?H Alkylation with Alkyl Peroxides
Ge, Liang,Jian, Wujun,Zhou, Huan,Chen, Shaowei,Ye, Changqing,Yu, Fei,Qian, Bo,Li, Yajun,Bao, Hongli
supporting information, p. 2522 - 2528 (2018/08/01)
A variety of alkyl peresters and alkyl diacyl peroxides, which are readily accessible from carboxylic acids, are utilized as general primary, secondary, and tertiary alkylating reagents for iron-catalyzed vinylic C?H alkylation of vinyl arenes, dienes, and 1,3-enynes. This transformation affords olefinic products in up to 98 % yield with high E/Z values. A broad range of functionalities, including carboxyl, boronic acid, methoxy, ester, amino, and halides, are tolerated. This protocol provides a facile approach to some olefins that are difficult to access, and hence, offers an alternative to existing systems. The synthetic utility of this method is demonstrated by late-stage functionalization of selected natural-product derivatives.
Iron-Catalyzed Dehydrative Alkylation of Propargyl Alcohol with Alkyl Peroxides to Form Substituted 1,3-Enynes
Ye, Changqing,Qian, Bo,Li, Yajun,Su, Min,Li, Daliang,Bao, Hongli
supporting information, p. 3202 - 3205 (2018/06/11)
This paper reports a new method for the generation of substituted 1,3-enynes, whose synthesis by other methods could be a challenge. The dehydrative decarboxylative cascade coupling reaction of propargyl alcohol with alkyl peroxides is enabled by an iron catalyst and alkylating reagents. Primary, secondary, and tertiary alkyl groups can be introduced into 1,3-enynes, affording various substituted 1,3-enynes in moderate to good yields. Mechanistic studies suggest the involvement of a radical-polar crossover pathway.
Aminopyridine-Borane Complexes as Hydrogen Atom Donor Reagents: Reaction Mechanism and Substrate Selectivity
Barth, Florian,Achrainer, Florian,Pütz, Alexander M.,Zipse, Hendrik
supporting information, p. 13455 - 13464 (2017/10/05)
Lewis base-borane complexes are shown to be potent hydrogen atom donors in radical chain reduction reactions. Results obtained in 1H, 11B, and 13C NMR measurements and kinetic experiments support a complex reaction mechanism involving the parent borane as well as its initial reaction products as active hydrogen atom donors. Efficient reduction reactions of iodides, bromides, and xanthates in apolar solvents rely on initiator systems generating oxygen-centered radicals under thermal conditions and pyridine-borane complexes carrying solubilizing substituents. In contrast to tin hydride reagents, the pyridine-boranes reduce xanthates faster than the corresponding iodides.
Iron-catalyzed C-H alkylation of heterocyclic C-H bonds
Babu, Kaki Raveendra,Zhu, Nengbo,Bao, Hongli
supporting information, p. 46 - 49 (2017/11/28)
An efficient, iron-catalyzed C-H alkylation of benzothiazoles by using alkyl diacyl peroxides and alkyl tertbutyl peresters which are readily accessible from carboxylic acids to synthesize 2-alkylbenzothiazoles is developed. This reaction is environmentally benign and compatible with a broad range of functional groups. Various primary, secondary, and tertiary alkyl groups can be efficiently incorporated into diverse benzothiazoles. The effectiveness of this method is illustrated by late-stage functionalization of biologically active heterocycles.
Method for producing acyl peroxides
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Page/Page column 4, (2010/02/17)
The invention relates to a method for producing acyl peroxides. According to said method, an acyl compound is reacted with an organic hydroperoxide and a base, the pH of the two-phase mixture so obtained is adjusted to 6 to 13, the obtained organic phase is extracted with an aqueous solution of a base and the aqueous extract is recirculated to the reaction step. The method according to the invention allows the recirculation of unreacted hydroperoxide to the reaction step.
METHOD FOR THE PRODUCTION OF ORGANIC PEROXIDES BY MEANS OF A MICROREACTION TECHNIQUE
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Page/Page column 6-7, (2009/03/07)
The invention provides a process for efficient and reliable preparation of organic peroxides, preferably dialkyl peroxides, peroxycarboxylic acids, peroxycarboxylic esters, diacyl peroxides, peroxycarbonate esters, peroxydicarbonates, ketone peroxides and perketals with the aid of at least one static micromixer and an apparatus for performing the process.
