Copper‐Catalyzed Oxidative Alkylation of Vinylic C β ‐H of Enamides with Cyclic Ethers

2019 ◽  
Vol 4 (23) ◽  
pp. 6954-6957 ◽  
Author(s):  
Ran Ding ◽  
Wang‐Gang Lu ◽  
Hao Ci ◽  
Yue‐Yuan Mao ◽  
Lei Liu
Keyword(s):  
Cyclic Ethers ◽  
Oxidative Alkylation

Co–Catalyzed Oxidative Alkylation between Styrenes and Cyclic Ethers via sp3 C−H Functionalization

2020 ◽  
Vol 5 (6) ◽  
pp. 2078-2081
Author(s):  
Rongxiang Chen ◽  
Kai‐Kai Wang ◽  
Zhan‐Yong Wang ◽  
Xueji Ma ◽  
Doudou Wang ◽  
...  
Keyword(s):  
Cyclic Ethers ◽  
Oxidative Alkylation

scholarly journals Co-Catalyzed Oxidative Alkylation between Styrenes and Cyclic Ethers via sp3 C−H Functionalization

2019 ◽  
Author(s):  
Rongxiang Chen ◽  
Kai-Kai Wang ◽  
Zhan-Yong Wang ◽  
Xueji Ma ◽  
Doudou Wang ◽  
...  
Keyword(s):  
Functional Group ◽  
Cyclic Ethers ◽  
Aerobic Conditions ◽  
Bond Functionalization ◽  
Simple Operation ◽  
Highly Efficient ◽  
Efficient Construction ◽  
Oxidative Alkylation

A new cobalt-catalyzed oxidative alkylation from readily available styrenes and ethers has been disclosed for a rapid and highly efficient construction of C−C bond via sp3 C−H bond functionalization. This methodology was demonstrated by good yields and functional group compatibility with simple operation, easily available starting materials, low catalyst loadings, and mild aerobic conditions.

Participation of 19-substituents in electrophilic additions to 6,7-unsaturated 5α-cholestane and B-homo 5α-cholestane derivatives; A case of competition between the participation of an ambident neighboring group and external nucleophile attack

1980 ◽  
Vol 45 (2) ◽  
pp. 559-583 ◽  
Author(s):  
Pavel Kočovský ◽  
Ladislav Kohout ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Hydrobromic Acid ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Neighboring Group ◽  
Acid Cleavage ◽  
Neighbouring Group Participation ◽  
Aqueous Perchloric Acid ◽  
The Difference ◽  
Electrophilic Additions

Hypobromous acid action upon the 6,7-unsaturated 19-substituted 5α-cholestans Va-Vc results in the formation of two types of products, the cyclic ethers IX as products of 5(O)n participation of the 19-substituent, and the bromohydrins X. All these compounds are formed from the 6α,7α-bromonium ions Va'-Vc'. Under the same conditions the B-homo-5α-cholestane derivatives VIIa-VIIc afforded solely the cyclic ethers XIV as products of 5(O)n participation of the 19-substituent in the cleavage of the bromonium ions VIIa'-VIIc'. Acid cleavage of the 6α,7α-epoxides VIb and VIc with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the cyclic ethers XI and the diols XII or bromohydrines XIII. The cyclic ethers XI arise by 5(O)n participation of the 19-substituent. The B-homo-6α, 7α-epoxide VIIIc on cleavage with aqueous perchloric acid have solely the cyclic ether XVc and by treatment with hydrobromic acid VIIIc afforded the mixture of XVc, as the main product, and of the bromohydrin XVIc. Discussed is the similarity of the bromonium ion cleavage with the fission of the corresponding epoxides, the mechanism of these reactions and the difference in the behaviour of the isomeric olefins Ia-c, IIIa-c, Va-c and VIIa-c and epoxides IIb,c, IVb,c, VIb,c and VIIIb,c. The competition between ambident neighbouring group participation and external nucleophile attack is discussed as well as the dependence of the products ratio on the nucleophilicity of the attacking species.

Boron insertion into alkyl ether bonds via zinc/nickel tandem catalysis

Science ◽  
2021 ◽  
Vol 372 (6538) ◽  
pp. 175-182
Author(s):  
Hairong Lyu ◽  
Ilia Kevlishvili ◽  
Xuan Yu ◽  
Peng Liu ◽  
Guangbin Dong
Keyword(s):  
Nickel Catalyst ◽  
Bioactive Compounds ◽  
Cyclic Ethers ◽  
Alkyl Ether ◽  
Tandem Catalysis ◽  
Mechanistic Studies ◽  
Alkyl Ethers ◽  
Nitrogen Substitution ◽  
Zinc Nickel

Mild methods to cleave the carbon-oxygen (C−O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C−O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly streamline preparation of bioactive compounds. Mechanistic studies reveal a cleavage-then-rebound pathway via zinc/nickel tandem catalysis.

Oxidative Alkylation/Alkynylation of Terminal Alkenes via Alkylaldehyde Decarbonylation and 1,2-Alkynyl Migration

2021 ◽  
Author(s):  
Jiajia Zhang ◽  
De Chen ◽  
yiqun qin ◽  
Wei Deng ◽  
Yongyue luo ◽  
...  
Keyword(s):  
Functional Group ◽  
Quaternary Carbon ◽  
Metal Free ◽  
Terminal Alkenes ◽  
Oxidative Alkylation

A metal-free oxidative alkene alkylation/alkynylation of 1,4-enyn-3-ols with alkylaldehydes has been achieved, which offers a general access to the challenging quaternary carbon-containing but-3-yn-1-ones. The method features with excellent functional group...

Ring-opening polymerization of cyclic ethers initiated by benzazaphosphole-W(CO)5/silver hexafluoroantimonate

2013 ◽  
Vol 52 (5) ◽  
pp. 664-670 ◽  
Author(s):  
Mohammed Ghalib ◽  
Sergej Lysenko ◽  
Peter G. Jones ◽  
Joachim W. Heinicke
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Cyclic Ethers
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