6270-03-7Relevant academic research and scientific papers
PREPARATION OF DIESTERS OF (METH)ACRYLIC ACID FROM EPOXIDES
-
Page/Page column 23, (2020/03/05)
The application relates to a process for preparing a (meth)acrylic acid diester by reacting a (meth)acrylic acid anhydride with an epoxide in the presence of a catalyst system comprising a first and/or second catalyst in combination with a co-catalyst. The first catalyst is a halide of Mg or a trifluoromethanesulfonate of a rare earth element; the second catalyst is a Cr(lll) salt; and the co- catalyst is a tertiary amine, a quaternary ammonium salt, a tertiary phosphine or a quaternary phosphonium salt.
Tandem Acid/Pd-Catalyzed Reductive Rearrangement of Glycol Derivatives
Ciszek, Benjamin,Fleischer, Ivana,Kathe, Prasad,Schmidt, Tanno A.
supporting information, p. 3641 - 3646 (2020/03/25)
Herein, we describe the acid/Pd-tandem-catalyzed transformation of glycol derivatives into terminal formic esters. Mechanistic investigations show that the substrate undergoes rearrangement to an aldehyde under [1,2] hydrogen migration and cleavage of an oxygen-based leaving group. The leaving group is trapped as its formic ester, and the aldehyde is reduced and subsequently esterified to a formate. Whereas the rearrangement to the aldehyde is catalyzed by sulfonic acids, the reduction step requires a unique catalyst system comprising a PdII or Pd0 precursor in loadings as low as 0.75 mol % and α,α′-bis(di-tert-butylphosphino)-o-xylene as ligand. The reduction step makes use of formic acid as an easy-to-handle transfer reductant. The substrate scope of the transformation encompasses both aromatic and aliphatic substrates and a variety of leaving groups.
Efficient and regioselective ring-opening of epoxides with carboxylic acid catalyzed by graphite oxide
Mirza-Aghayan, Maryam,Tavana, Mahdieh Molaee,Niazi, Elaheh Golam Alipour,Boukherroub, Rabah
, p. 532 - 538 (2020/07/17)
An efficient, simple and regioselective ring-opening reaction of epoxides with various carboxylic acids under metal-free conditions is reported. The ring-opening of epoxides takes place in the presence of graphite oxide as an efficient and available catalyst to produce the corresponding 2-hydroxy monoester and 1,2-diester derivatives in good yields. Regioselective attack of the nucleo-phile, short reaction times, metal-free conditions and reusability of catalyst are among the advantages of the present protocol.
4-Imidazol-1-yl-butane-1-sulfonic acid ionic liquid: Synthesis, structural analysis, physical properties and catalytic application as dual solvent-catalyst
Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie,Juan, Joon Ching
, p. 866 - 878 (2019/07/12)
4-Imidazol-1-yl-butane-1-sulfonic acid (ImBu-SO3H) has been successfully synthetized and fully characterized by FT-IR and high-resolution NMR spectroscopy (1H, 13C). The “plausible” alternative structures of ImBu-SO3H were discussed on the basis of its NMR data. The ionic liquid showed interesting dual solvent-catalyst property, which was studied experimentally for the acetylation of a variety of functionalized alcohols, phenols, thiols, amines and α-tocopherol (α-CTP) as the most active form of vitamin E with acetic anhydride and which provided good yields within a short reaction time. ImBu-SO3H was successfully recycled by product extraction with an average recovered yield of 82% for 5 subsequent runs. The catalytic activity of the recycled ImBu-SO3H showed almost no loss even after five consecutive runs.
SYNTHESIS OF HYPERVALENT IODINE REAGENTS WITH DIOXYGEN
-
Paragraph 0187-0188, (2019/01/15)
Methods of synthesis of hypervalent iodine reagents and methods for oxidation of organic compounds are disclosed.
Alternative Strategies with Iodine: Fast Access to Previously Inaccessible Iodine(III) Compounds
Hokamp, Tobias,Mollari, Leonardo,Wilkins, Lewis C.,Melen, Rebecca L.,Wirth, Thomas
supporting information, p. 8306 - 8309 (2018/06/29)
Non-iodinated arenes can be easily and selectively converted into (diacetoxyiodo)arenes in a single step under mild conditions by using iodine triacetates as reagents. The oxidative step is decoupled from the synthesis of hypervalent iodine(III) reagents, which can now be prepared conveniently in a one-pot synthesis for subsequent reactions without prior purification. The chemistry of iodine triacetates was also expanded to heteroatom ligand exchanges to form novel inorganic hypervalent iodine compounds.
B2pin2-Mediated Palladium-Catalyzed Diacetoxylation of Aryl Alkenes with O2 as Oxygen Source and Sole Oxidant
Huang, Jiuzhong,Ouyang, Lu,Li, Jianxiao,Zheng, Jia,Yan, Wuxin,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 5090 - 5093 (2018/09/12)
A novel palladium-catalyzed alkene diacetoxylation with dioxygen (O2) as both the sole oxidant and oxygen source is developed, which was identified by 18O-isotope labeling studies. Control experiments suggested that bis(pinacolato)diboron (B2pin2) played a dominant intermediary role in the formation of a C-O bond. This method performed good functional group tolerance with moderate to excellent yields, which could be successfully applied to the late-stage modification of natural products. Furthermore, an atmospheric pressure of dioxygen enhances the practicability of the protocol.
Method for triggering hydroxy selective acylation of dihydric alcohol or polyhydric alcohol by catalytic amount of organic amine
-
Paragraph 0020, (2018/10/27)
The invention belongs to the field of organic chemical engineering, and particularly provides a method for triggering hydroxy selective acylation of dihydric alcohol or polyhydric alcohol by a catalytic amount of organic amine. According to the method, dihydric alcohol or polyhydric alcohol dissolves in an appropriate amount of organic solvents, a chemical amount of anhydride and the catalytic amount of organic amine are added, N,N-diisopropylethylamine is added particularly, reaction is conducted at the temperature of 0-50 DEG C for 4-12 hours, and high-selectivity acylation on specific hydroxyl can be realized. The method has the advantages that reaction conditions are mild, the method is simple and convenient to operate, inhibitors are green, environmentally friendly, low in cost and easy to get, and the method has wide application value in labs and industries.
A Phosphonium Ylide as an Ionic Nucleophilic Catalyst for Primary Hydroxyl Group Selective Acylation of Diols
Toda, Yasunori,Sakamoto, Tomoyuki,Komiyama, Yutaka,Kikuchi, Ayaka,Suga, Hiroyuki
, p. 6150 - 6154 (2017/09/15)
Carbonyl-stabilized phosphonium ylides exhibit great utility in modern organic synthesis, and they are known as an ambident nucleophile at the carbonyl oxygen atom and at the α-carbon atom. However, they have found limited use as catalysts. We focused on the inherent nucleophilicity of the oxygen atom to develop an ionic nucleophilic catalysis, and the phosphonium ylide-catalyzed primary alcohol selective acylation of mixed diols with acid anhydrides has been demonstrated. Mechanistic studies revealed the behavior of a catalyst, which would contribute to the field of ylide chemistry.
Vicinal Difunctionalization of Alkenes under Iodine(III) Catalysis involving Lewis Base Adducts
Aertker, Kristina,Rama, Raquel J.,Opalach, Julita,Mu?iz, Kilian
, p. 1290 - 1294 (2017/04/18)
The influence of a 2-pyridinyl substituent on the catalytic performance of aryl iodides as catalyst in iodine(III) chemistry was explored. An efficient Lewis base adduct between the pyridine nitrogen and the electrophilic iodine(III) center was identified and confirmed by X-ray analysis. This arrangement was shown to generate a kinetically competent superior catalyst structure for the catalytic dioxygenation of alkenes. It introduces the concept of Lewis base adduct formation as a kinetic factor in iodine(I/III) catalysis. (Figure presented.).
