- Directional migration method of benzoyl between hydroxyls based on sulfoacid catalysis
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The invention discloses a directional migration method of benzoyl between hydroxyls based on sulfoacid catalysis, and relates to the technical field of chemical synthesis. Specifically, under the catalysis condition of sulphonic acid, the migration of acyl groups of the benzoyl is selectively completed through via of an ortho-ester intermediate in a high region, the characteristics of the migration are shown as follows: two hydroxyls of 5-ortho-ester rings or 6-ortho-ester rings can be formed in space, and the benzoyl can be migrated from secondary hydroxyls or tertiary hydroxyls to primary hydroxyls, and can be migrated from upright-position secondary hydroxyls to flat-position hydroxyls. According to the directional migration method disclosed by the invention, the sulfoacid is used for promoting acyl functional groups in a substrate to generate a 1,2-migration reaction or 1,3-migration reaction, the whole synthesis reaction condition is mild, the operation is simple, and atoms are economic.
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Paragraph 0094-0098
(2020/02/14)
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- Stannous chloride as a low toxicity and extremely cheap catalyst for regio-/site-selective acylation with unusually broad substrate scope
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This work reports stannous chloride (SnCl2)-catalyzed regio-/site-selective acylation with unusually broad substrate scope. In addition to 1,2- and 1,3-diols and glycosides containing cis-vicinal diol, the substrate scope also includes glycosides without cis-vicinal diol. For such a substrate scope, usually, only methods using stoichiometric amounts of organotin reagents can lead to the same protection pattern with high selectivities and highly isolated yields (84-97% in most cases). Therefore, SnCl2, as a low toxicity and extremely cheap reagent, should be the best catalyst for regio-/site-selective acylation compared with any previously reported reagents. This journal is
- Dong, Hai,Feng, Guang-Jing,Luo, Tao,Lv, Jian,Yu, Jian-Cheng
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supporting information
p. 6936 - 6942
(2020/11/09)
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- Regioselective Sulfonylation/Acylation of Carbohydrates Catalyzed by FeCl3 Combined with Benzoyltrifluoroacetone and Its Mechanism Study
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A catalytic amount of FeCl3 combined with benzoyl trifluoroacetone (Hbtfa) (FeCl3/Hbtfa = 1/2) was used to catalyze sulfonylation/acylation of diols and polyols using diisopropylethylamine (DIPEA) or potassium carbonate (K2CO3) as a base. The catalytic system exhibited high catalytic activity, leading to excellent isolated yields of sulfonylation/acylation products with high regioselectivities. Mechanism studies indicated that FeCl3 initially formed [Fe(btfa)3] (btfa = benzoyl trifluoroacetonate) with twice the amount of Hbtfa under basic conditions in the solvent acetonitrile at room temperature. Then, Fe(btfa)3 and two hydroxyl groups of the substrates formed a five- or six-membered ring intermediate in the presence of the base. The subsequent reaction between the cyclic intermediate and a sulfonylation reagent led to the selective sulfonylation of the substrate. All key intermediates were captured in the high-resolution mass spectrometry assay, therefore demonstrating this mechanism for the first time.
- Dong, Hai,Liu, Yu,Lv, Jian,Zhu, Jia-Jia
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p. 3307 - 3319
(2020/03/25)
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- An inexpensive catalyst, Fe(acac)3, for regio/site-selective acylation of diols and carbohydrates containing a 1,2-: Cis -diol
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This work describes the [Fe(acac)3] (acac = acetylacetonate)-catalyzed, regio/site-selective acylation of 1,2- and 1,3-diols and glycosides containing a cis-vicinal diol. The iron(iii) catalysts initially formed cyclic dioxolane-type intermediates with substrates between the iron(iii) species and vicinal diols, and the efficient and selective acylation of one hydroxyl group was subsequently achieved by adding acylation reagents in the presence of diisopropylethylamine (DIPEA) under mild conditions. This reaction generally produced high selectivities and highly isolated yields with the same protection pattern as that achieved with dibutyl tinoxide-mediated schemes.
- Lv, Jian,Ge, Jian-Tao,Luo, Tao,Dong, Hai
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supporting information
p. 1987 - 1991
(2018/05/23)
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- Regioselective benzoylation of diols and carbohydrates by catalytic amounts of organobase
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A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DB
- Lu, Yuchao,Hou, Chenxi,Ren, Jingli,Xin, Xiaoting,Xu, Hengfu,Pei, Yuxin,Dong, Hai,Pei, Zhichao
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- An Efficient Method for the Chemoselective Preparation of Benzoylated 1,2-Diols from Epoxides
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A very efficient and highly regioselective ring-opening reaction of epoxides with benzoic acid and its derivatives in the presence of cat. amount of tetrabutylammonium bromide (TBAB) in anhydrous acetonitrile has been developed. This effective method is useful for the preparation of selectively protected diols as precursor for many organic syntheses such as those of acyclic nucleosides and other synthetic purposes. The advantages of this method are efficiency, selectivity, low cost, and the applicability in large-scale synthesis of β-benzoyloxyalkanols.
- Khalafi-Nezhad,Soltani Rad,Khoshnood
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p. 2552 - 2558
(2007/10/03)
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- Process for preparing an organic compound from an oxirane-containing compound in the presence of a tris(triaminophosphoranylideneamino)phosphine oxide
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A process for preparing an organic compound, comprising conducting an organic reaction in the presence of a phosphine oxide represented by formula (1); where R1 is the same or different and each represents a hydrogen or hydrocarbon group with 1 to 10 carb
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- MECHANISM OF REACTION OF PHENYL GLYCIDYL ETHER WITH PHENYL BENZOATE IN THE PRESENCE OF WATER
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The reaction of phenyl glycidyl ether with phenyl benzoate in the presence of water was investigated by adsorption liquid chromatography.
- Pankratov, V. A.,Frenkel', Ts. M.,Shvorak, A. E.,Komarova, L. I.,Grozdov, A. G.,Maslov, V. A.
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p. 118 - 120
(2007/10/02)
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- MECHANISM OF THE REACTION OF GLYCIDYL ESTERS WITH CARBOXYLIC ACIDS
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The kinetics of the reactions of 1-phenoxy-2,3-epoxypropane and 2,3-epoxypropylbenzoate with carboxylic acids were investigated.A new reaction mechanism is proposed to explain the anomalously high reactivity of the glycidyl esters.The mechanism involves protonation of the oxygen of the carbonyl group in the ester followed by intramolecular electrophilic attack on the oxirane oxygen by the carbonyl carbon atom, accompanied by opening of the epoxide ring and transfer of the acyl fragment in the glycidyl ester molecule.
- Klebanov, M. S.,Kir'yazev, F. Yu.,Chervinskii, A. Yu.,Shologon, I. M.
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p. 2193 - 2196
(2007/10/02)
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