Scalable Synthesis of a Chiral Selenium π-Acid Catalyst and Its Use in Enantioselective Iminolactonization of β,γ-Unsaturated Amides

Synlett ◽  
2019 ◽  
Vol 30 (14) ◽  
pp. 1679-1682 ◽  
Author(s):  
Yuta Otsuka ◽  
Yuto Shimazaki ◽  
Hitoshi Nagaoka ◽  
Keiji Maruoka ◽  
Takuya Hashimoto

Chiral selenium π-acid catalysis has for a long time been lagging behind other areas of asymmetric catalysis due to a lack of highly enantioselective catalysts. In this regard, we recently developed the first chiral selenium π-acid catalyst which performs the oxidative cyclization of β,γ-unsaturated carboxylic acids with high enantioselectivities. We report herein our improved synthesis of this chiral selenium catalyst, which allows access to a large quantity of the catalyst as the diselenide. In addition, the catalyst is tested in the oxidative cyclization of N-methoxy β,γ-unsaturated amides to give iminolactones with high enantioselectivities.

Synthesis ◽  
2017 ◽  
Vol 49 (13) ◽  
pp. 2907-2912 ◽  
Author(s):  
Kensuke Kiyokawa ◽  
Satoshi Minakata ◽  
Kenta Takemoto ◽  
Shunsuke Yahata ◽  
Takumi Kojima

The oxidative cyclization of β-substituted β,γ-unsaturated carboxylic acids using a hypervalent iodine reagent to provide 4-substituted furan-2-one products, is reported. In this cyclization, the use of a highly electrophilic PhI(OTf)2, which is in situ prepared from PhI(OAc)2 and Me3SiOTf, is crucial. Depending on the substitution pattern at the α-position of the substrates, furan-2(5H)-ones or furan-2(3H)-ones are produced. Thus, the present method offers a useful tool for accessing various types of 4-substituted furan-2-ones that are important structural motifs in the field of organic chemistry and medicinal chemistry.


2019 ◽  
Vol 23 (11) ◽  
pp. 1168-1213 ◽  
Author(s):  
Samar Noreen ◽  
Ameer Fawad Zahoor ◽  
Sajjad Ahmad ◽  
Irum Shahzadi ◽  
Ali Irfan ◽  
...  

Background: Asymmetric catalysis holds a prestigious role in organic syntheses since a long time and chiral inductors such as ligands have been used to achieve the utmost desired results at this pitch. The asymmetric version of Tsuji-Trost allylation has played a crucial role in enantioselective synthesis. Various chiral ligands have been known for Pdcatalyzed Asymmetric Allylic Alkylation (AAA) reactions and exhibited excellent catalytic potential. The use of chiral ligands as asymmetric inductors has widened the scope of Tsuji-Trost allylic alkylation reactions. Conclusion: Therefore, in this review article, a variety of chiral inductors or ligands have been focused for palladium catalyzed asymmetric allylic alkylation (Tsuji-Trost allylation) and in this regard, recently reported literature (2013-2017) has been described. The use of ligands causes the induction of enantiodiscrimination to the allylated products, therefore, the syntheses of various kinds of ligands have been targeted by many research groups to employ in Pd-catalyzed AAA reactions.


1980 ◽  
Vol 45 (6) ◽  
pp. 1655-1661 ◽  
Author(s):  
Robert Ponec

Various quantum chemical approaches to the problem of transmission of the substituent effect were compared. It was shown that inclusion of the electronic repulsion (field effect) was necessary to give a true picture of differences in ρ constants for reactions of the cis and trans isomers of substituted unsaturated carboxylic acids; the same holds for an adequate description of transmission of the substituent effect from the meta position on a given skeleton.


2020 ◽  
Vol 11 (21) ◽  
pp. 5572-5576 ◽  
Author(s):  
Noboru Hayama ◽  
Yusuke Kobayashi ◽  
Eriko Sekimoto ◽  
Anna Miyazaki ◽  
Kiyofumi Inamoto ◽  
...  

An asymmetric thia-Michael addition of arylthiols to α,β-unsaturated carboxylic acids using a thiourea catalyst that bears arylboronic acid and tertiary amine moieties is reported.


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