scholarly journals Chiral Brønsted acid-catalyzed intramolecular SN2′ reaction for enantioselective construction of a quaternary stereogenic center

2018 ◽  
Vol 9 (26) ◽  
pp. 5747-5757 ◽  
Author(s):  
Masahiro Shimizu ◽  
Jun Kikuchi ◽  
Azusa Kondoh ◽  
Masahiro Terada
Keyword(s):  
Substitution Reaction ◽  
Allylic Substitution ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Sn2 Reaction ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid ◽  
Stereogenic Center

Construction of a quaternary stereogenic center was accomplished through the enantioselective intramolecular allylic substitution reaction of bis-trichloroacetimidate catalyzed by a chiral phosphoramide derivative.

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.

Chiral Brønsted acid-catalyzed hydrophosphonylation of imines—DFT study on the effect of substituents of phosphoric acid

Tetrahedron ◽  
2009 ◽  
Vol 65 (26) ◽  
pp. 4950-4956 ◽  
Author(s):  
Takahiko Akiyama ◽  
Hisashi Morita ◽  
Prabhakar Bachu ◽  
Keiji Mori ◽  
Masahiro Yamanaka ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Dft Study ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Effect Of Substituents ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid

Chiral Brønsted Acid Catalyzed Dynamic Kinetic Asymmetric Hydroamination of Racemic Allenes and Asymmetric Hydroamination of Dienes

2019 ◽  
Vol 131 (21) ◽  
pp. 7166-7170 ◽  
Author(s):  
Jin‐Shun Lin ◽  
Tao‐Tao Li ◽  
Guan‐Yuan Jiao ◽  
Qiang‐Shuai Gu ◽  
Jiang‐Tao Cheng ◽  
...  
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid
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