scholarly journals Re2O7-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

2013 ◽  
Vol 9 ◽  
pp. 1526-1532 ◽  
Author(s):  
Wantanee Sittiwong ◽  
Michael W Richardson ◽  
Charles E Schiaffo ◽  
Thomas J Fisher ◽  
Patrick H Dussault
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Silyl Ethers ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Nitrogen Nucleophiles

Re(VII) oxides catalyze the acetalization, monoperoxyacetalization, monothioacetalization and allylation of hemiacetals. The reactions, which take place under mild conditions and at low catalyst loadings, can be conducted using hemiacetals, the corresponding O-silyl ethers, and, in some cases, the acetal dimers. Aldehydes react under similar conditions to furnish good yields of dithioacetals. Reactions of hemiacetals with nitrogen nucleophiles are unsuccessful. 1,2-Dioxolan-3-ols (peroxyhemiacetals) undergo Re(VII)-promoted etherification but not allylation. Hydroperoxyacetals (1-alkoxyhydroperoxides) undergo selective exchange of the alkoxide group in the presence of either Re2O7 or a Brønsted acid.

Brønsted acid-catalyzed 1,2-fluorine migration with fluoroepoxides

2015 ◽  
Vol 44 (45) ◽  
pp. 19636-19641 ◽  
Author(s):  
Tao Luo ◽  
Rui Zhang ◽  
Xiao Shen ◽  
Wei Zhang ◽  
Chuanfa Ni ◽  
...  
Keyword(s):  
Fluorine Atom ◽  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Atom Economy ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Bronsted Acid Catalysis

An efficient 1,2-fluorine migration reaction was realized under Brønsted acid catalysis in the absence of an external fluorinating source. The high fluorine atom economy and very mild conditions make this reaction a promising protocol for the construction of the C–F bond.

Organic Photoredox Catalytic α-C(sp3)–H Phosphorylation of Saturated Aza-Heterocycles

2021 ◽  
Author(s):  
Ming-Jun Yi ◽  
Teng-Fei Xiao ◽  
Wen-Hui Li ◽  
Yi-Fan Zhang ◽  
Pen-Ji Yan ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Metal Free ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

A metal-free C(sp3)–H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Brønsted acid catalysis was established under mild conditions. This protocol provided a straightforward and economic access...

An uncommon use of irradiated flavins: Brønsted acid catalysis

2020 ◽  
Vol 56 (42) ◽  
pp. 5661-5664
Author(s):  
Yukihiro Arakawa ◽  
Tomohiro Mihara ◽  
Hiroki Fujii ◽  
Keiji Minagawa ◽  
Yasushi Imada
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Acid Catalysis ◽  
Light Irradiation ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

Visible light irradiation to flavins in the presence of thiols and O2 provides Brønsted acidic species that can be used as efficient catalysts for thioacetalizations and for Mannich-type reactions under non-irradiation and mild conditions.

Nitrile assisted, Brønsted acid catalyzed regio and stereoselective diarylphosphonylation of allyl silyl ethers

2010 ◽  
Vol 8 (15) ◽  
pp. 3480 ◽  
Author(s):  
Chun-Yu Ho ◽  
Chun-Wa Chan ◽  
Siu-Kwan Wo ◽  
Zhong Zuo ◽  
Lai-Ying Chan
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Silyl Ethers ◽  
Brönsted Acid ◽  
Acid Catalyzed

Improved Synthetic Method for 5-[(Phenylthio)methyl]oxazoline Derivatives: Electrophilic Cyclization of Allylic Amide Using a Brønsted Acid and Tetrabutylammonium Chloride under Mild Conditions

Synlett ◽  
2020 ◽  
Vol 31 (08) ◽  
pp. 813-817
Author(s):  
Yoshihiro Nagao ◽  
Kou Hiroya
Keyword(s):  
Electrophilic Cyclization ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Powerful Method ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Reaction Proceeds ◽  
Tetrabutylammonium Chloride ◽  
Oxazoline Derivatives

The synthesis of oxazolines using electrophilic cyclization of allylic amide is a simple and powerful method. However, cyclization involving arylsulfenylation requires harsh reaction conditions. We found that the reaction proceeds under mild heating conditions with the combination of a Brønsted acid and tetrabutylammonium chloride. This method enabled the synthesis of 5-[(arylsulfenyl)methyl]oxazoline derivatives under mild conditions and demonstrated high tolerance for various functional groups.

Bronsted acid catalysed chemo- and ortho-selective aminomethylation of phenol

2021 ◽  
Author(s):  
Zhiqiong Tang ◽  
Dongdong Li ◽  
Yidi Yue ◽  
Dan Peng ◽  
Lu Liu
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Available N ◽  
Mild Conditions ◽  
Selective Functionalization ◽  
Brönsted Acid

We have developed a Bronsted acid catalysed highly ortho-selective functionalization of free phenols with readily available N,O-acetals under mild conditions, furnishing various corresponding aminomethylated phenol products in moderate to excellent...

Amide directed hydrocarboxylation of N-allylacetamide catalyzed by the aqueous Pd - tppts - Brønsted acid system (tppts = P(C6H4-m-SO3Na)3)1

2001 ◽  
Vol 79 (5-6) ◽  
pp. 688-692 ◽  
Author(s):  
Göran Verspui ◽  
Gábor Besenyei ◽  
Roger A Sheldon
Keyword(s):  
Substitution Reaction ◽  
Aqueous Media ◽  
Propanoic Acid ◽  
Allylic Substitution ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The Pd - tppts - HOTs (tppts = P(C6H4-m-SO3Na)3, HOTs = p-toluenesulfonic acid) catalyzed hydrocarboxylation of N-allylacetamide in an aqueous medium afforded 4-acetamidobutyric acid and 3-acetamido-2-methylpropanoic acid under mild conditions, with a high regioselectivity towards the linear isomer. During the hydrocarboxylation an acid catalyzed hydrolysis of the amide moieties of both the substrate and the products took place, as well as the formation of acetamide and propanal, presumably via a Pd-catalyzed allylic substitution reaction of N-allylacetamide. The hydrolysis reaction was suppressed by lowering the amount of Brønsted acid cocatalyst (HOTs) or by employing a weaker Brønsted acid such as propanoic acid. The allylic substitution reaction was minimized by increasing the CO pressure but unfortunately this caused a decrease in the regioselectivity. A sudden inhibition took place after ca. 70% conversion, presumably caused by one of the side products. By increasing the tppts concentration to 13.1 mmol L-1 (20 equiv per Pd) the inhibition was circumvented and a quantitative conversion of N-allylacetamide was achieved.Key words: aqueous media, olefins, palladium, hydrocarboxylation, N-allylacetamide.

Diastereoselective synthesis of 1,3-disubstituted isoindolines and sultams via bronsted acid catalysis

2018 ◽  
Vol 54 (80) ◽  
pp. 11292-11295 ◽  
Author(s):  
Ye Tao ◽  
Scott R. Gilbertson
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Diastereoselective Synthesis ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

Isoindolines and sultams formed under mild conditions.

scholarly journals Brønsted Acid Catalysed Aerobic Reduction of Olefins by Diimide Generated In Situ from Hydrazine

SynOpen ◽  
2017 ◽  
Vol 01 (01) ◽  
pp. 0011-0014
Author(s):  
Yukihiro Arakawa ◽  
Takahiro Kohda ◽  
Keiji Minagawa ◽  
Yasushi Imada
Keyword(s):  
Bronsted Acids ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Brönsted Acid

Aerobic reduction of olefins with hydrazine was proven to be efficiently catalysed by readily available Brønsted acids, such as p-tolu­enesulfonic acid monohydrate, providing hydrogenated products in very good yields and chemoselectivity under mild conditions.

Brønsted Acid Catalyzed Cyclization of Inert N-Substituted Pyrroles to Benzo[f]pyrrolo[1,2-a][1,4]diazepines

Synlett ◽  
2021 ◽  
Author(s):  
Jinlong Zhang ◽  
Gaoxi Jiang ◽  
Zeng Gao ◽  
Jinlong Qian ◽  
Huameng Yang
Keyword(s):  
Ring Closure ◽  
Acid Catalysts ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Intermolecular Cyclization ◽  
Chiral Phosphoric Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
High Yields

AbstractTwo approaches involving intramolecular and intermolecular cyclization, respectively, have been developed for the direct and practical construction of a series of important benzo[f]pyrrolo[1,2-a][1,4]azepines by using Brønsted acid catalysts. Upon catalysis by TsOH, the intramolecular dehydroxylation/ring closure of 3-hydroxy-2-[2-(1H-pyrrol-1-yl)benzyl]isoindolin-1-ones provided various racemic benzo[f]pyrrolo[1,2-a][1,4]azepines in high yields. Furthermore, enantioenriched benzo[f]pyrrolo[1,2-a][1,4]azepines were also obtained by chiral phosphoric acid catalyzed intermolecular addition of [2-(1H-pyrrol-1-yl)phenyl]methanamines to 2-formylbenzoates under mild conditions.

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