Oxidative Cyclization of β,γ-Unsaturated Carboxylic Acids Using Hypervalent Iodine Reagents: An Efficient Synthesis of 4-Substituted Furan-2-ones

Synthesis ◽  
2017 ◽  
Vol 49 (13) ◽  
pp. 2907-2912 ◽  
Author(s):  
Kensuke Kiyokawa ◽  
Satoshi Minakata ◽  
Kenta Takemoto ◽  
Shunsuke Yahata ◽  
Takumi Kojima
Keyword(s):  
Organic Chemistry ◽  
Carboxylic Acids ◽  
Present Method ◽  
Medicinal Chemistry ◽  
Oxidative Cyclization ◽  
Hypervalent Iodine ◽  
Efficient Synthesis ◽  
Substitution Pattern ◽  
Unsaturated Carboxylic Acids

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.

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
Keyword(s):  
Carboxylic Acids ◽  
Asymmetric Catalysis ◽  
Acid Catalysis ◽  
Acid Catalyst ◽  
Oxidative Cyclization ◽  
Unsaturated Carboxylic Acids ◽  
Long Time ◽  
Scalable Synthesis ◽  
Enantioselective Catalysts

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.

scholarly journals Stereoselective Oxidative Cyclization of N-Allyl Benzamides to Oxazolines

2021 ◽  
Author(s):  
Ayham Abazid ◽  
Tom-Niklas Hollwedel ◽  
Boris Nachtsheim
Keyword(s):  
Oxidative Cyclization ◽  
Hypervalent Iodine ◽  
Iodine Compound

This manuscript describes a highly enantioselective oxidative cyclization of N-Allyl Benzamides and derivatives thereof. This method uses a chiral triazole-based iodine catalyst to generate a hypervalent iodine compound in situ as the active catalytic species. Besides oxazolines, other N-heterocylces such as thiazolines, imidazolines as well as oxanines can be generated in high optical purities. <br>

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