scholarly journals Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

2016 ◽  
Vol 12 ◽  
pp. 2189-2196 ◽  
Author(s):  
Katrina Tait ◽  
Oday Alrifai ◽  
Rebecca Boutin ◽  
Jamie Haner ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Tertiary Alcohol ◽  
Optimal Conditions ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene derivatives using alcohol nucleophiles were investigated. The optimal conditions were found to be 10 mol % PdCl2(CH3CN)2 in methanol, offering yields up to 92%. The reaction was successful using primary, secondary and tertiary alcohol nucleophiles and was compatible with a variety of substituents on cyclopropanated oxabenzonorbornadiene. With unsymmetrical C1-substituted cyclopropanated 7-oxabenzonorbornadienes, the regioselectivity of the reaction was excellent, forming only one regioisomer in all cases.

scholarly journals Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

2016 ◽  
Vol 12 ◽  
pp. 239-244 ◽  
Author(s):  
Michael Edmunds ◽  
Mohammed Abdul Raheem ◽  
Rebecca Boutin ◽  
Katrina Tait ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Optimal Conditions ◽  
Aryl Iodides ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed

Palladium-catalyzed ring-opening reactions of C1 substituted 7-oxanorbornadiene derivatives with aryl iodides were investigated. The optimal conditions for this reaction were found to be PdCl2(PPh3)2, ZnCl2, Et3N and Zn in THF. Both steric and electronic factors played a role in the outcome of the reaction as increasing the steric bulk on the bridgehead carbon decreased the yield. These reactions were found to be highly regioselective, giving only one of the two possible regioisomers in all cases. A diverse collection of novel, highly substituted biphenyl derivatives were obtained.

Palladium-Catalyzed Synthesis of Polysubstituted Pyrazoles by Ring-Opening Reactions of 2H-Azirines with Hydrazones

Synlett ◽  
2020 ◽  
Author(s):  
Jiaan Shao ◽  
Ke Shu ◽  
Wenteng Chen ◽  
Shuangrong Liu ◽  
Huajian Zhu ◽  
...  
Keyword(s):  
Ring Opening ◽  
Chemical Conversion ◽  
Alternative Route ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed ◽  
Plausible Mechanism

AbstractA palladium–catalyzed ring-opening reaction of 2H-azirines with hydrazones has been developed. This protocol provides an alternative route for the construction of various polysubstituted pyrazoles with a wide substrate scope. Moreover, a plausible mechanism is proposed for this reaction, which should further enrich the chemical conversion of 2H-azirines.

ChemInform Abstract: Regioselective Palladium-Catalyzed Ring-Opening Reactions of C1-Substituted Oxabenzonorbornadienes.

ChemInform ◽  
2015 ◽  
Vol 46 (10) ◽  
pp. no-no
Author(s):  
Mohammed Abdul Raheem ◽  
Michael Edmunds ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed

ChemInform Abstract: Regioselective Palladium-Catalyzed Ring-Opening Reactions of C1-Substituted Oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates.

ChemInform ◽  
2016 ◽  
Vol 47 (21) ◽  
Author(s):  
Michael Edmunds ◽  
Mohammed Abdul Raheem ◽  
Rebecca Boutin ◽  
Katrina Tait ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed

Electrophilic Ring Opening of Small Heterocycles

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5307-5319 ◽  
Author(s):  
Chuan Wang
Keyword(s):  
Ethylene Oxide ◽  
Functional Groups ◽  
Organic Synthesis ◽  
Ring Opening ◽  
Building Blocks ◽  
Nickel Titanium ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed ◽  
Ring Opening Of Epoxides ◽  
Nucleophilic Ring Opening

Small heterocycles, such as epoxides, aziridines, and ox­etanes are among the most useful building blocks in organic synthesis. Through electrophilic ring opening of these molecules, various electrophilic functional groups can be installed, which cannot be achieved via classic nucleophilic ring-opening reactions. In this review, the developments of electrophilic ring opening of small heterocycles are surveyed and organized according to the types of metal promoters.1 Introduction2 Electrophilic Ring Opening of Small Heterocycles Using Stoichiometric Metals2.1 Lithium-Mediated Electrophilic Ring Opening of Epoxides and Oxetanes2.2 Chromium-Mediated Electrophilic Ring Opening of Vinyl Epoxides2.3 Tin-Mediated Electrophilic Ring Opening of Vinyl Epoxides2.4 Samarium-Mediated Electrophilic Ring Opening of Vinyl and Alkynyl Epoxides2.5 Titanium-Mediated Electrophilic Ring Opening of Epoxides2.6 Platinum, Palladium, and Nickel-Mediated Electrophilic Ring Opening of 1,1-Dimethyl Ethylene Oxide3 Catalytic Electrophilic Ring Opening of Small Heterocycles3.1 Titanium-Catalyzed Electrophilic Ring Opening of Epoxides3.2 Palladium-Catalyzed Electrophilic Ring Opening of Vinyl and Alkynyl Small Heterocycles3.3 Iron-Catalyzed Electrophilic Ring Opening of Oxetanes3.4 Scandium-Catalyzed Electrophilic Ring Opening of Vinyl Epoxides3.5 Iridium-Catalyzed Electrophilic Ring Opening of 2-Methyl 2-Vinyl­oxiranes3.6 Nickel-Catalyzed Electrophilic Ring Opening of Epoxides and Aziridines3.7 Nickel–Titanium-Cocatalyzed Electrophilic Ring Opening of Epoxides4 Summary

Palladium-catalyzed ring-opening reactions of 1-acetyl-4-vinyl-2-azetidinones and 1-sulfonyl-2-vinylazetidines. Role of intramolecular participation of amide anion

Tetrahedron ◽  
1995 ◽  
Vol 51 (18) ◽  
pp. 5331-5340 ◽  
Author(s):  
Akiharu Satake ◽  
Hideo Ishii ◽  
Isao Shimizu ◽  
Yoichi Inoue ◽  
Hajime Hasegawa ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed

Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabenzonorbornadienes

2014 ◽  
Vol 92 (9) ◽  
pp. 888-895 ◽  
Author(s):  
Mohammed Abdul Raheem ◽  
Michael Edmunds ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Aryl Group ◽  
Aryl Iodide ◽  
Electronic Nature ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed ◽  
High Yields ◽  
Nucleophilic Ring Opening

The effect of ethyl and methoxycarbonyl substitution on the C1 position of oxabenzonorbornadienes undergoing palladium-catalyzed nucleophilic ring opening was investigated with a variety of aryl iodide nucleophiles. Electron-withdrawing groups in the C1 position or on the aryl iodide afforded lower yields and led to aromatization of products. The presence of an electron-donating group in either position provided high yields in all cases. Despite variances in electronic nature, all trials produced a single regioisomeric product resulting from addition of the aryl group to the olefin carbon farthest from the C1 substituent. Based on these findings, a mechanism has also been proposed.

scholarly journals Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols

2017 ◽  
Vol 13 ◽  
pp. 2888-2894 ◽  
Author(s):  
Katrina Tait ◽  
Alysia Horvath ◽  
Nicolas Blanchard ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Tertiary Alcohol ◽  
Acid Catalysts ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Acid Catalyzed

The acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicylic alkene using alcohol nucleophiles were investigated. Although this acid-catalyzed ring-opening reaction did not cleave the cyclopropane unit as planned, this represent the first examples of ring-openings of cyclopropanated 3-aza-2-oxabicyclo[2.2.1]alkenes that lead to the cleavage of the C–O bond instead of the N–O bond. Different acid catalysts were tested and it was found that pyridinium toluenesulfonate in methanol gave the best yields in the ring-opening reactions. The scope of the reaction was successfully expanded to include primary, secondary, and tertiary alcohol nucleophiles. Through X-ray crystallography, the stereochemistry of the product was determined which confirmed an SN2-like mechanism to form the ring-opened product.

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