Header

UZH-Logo

Maintenance Infos

Experimental and Computational Studies on Stepwise [3+2]-Cycloadditions of Diaryldiazomethanes with Electron-Deficient Dimethyl (E)- and (Z)-2,3-Dicyanobutenedioates


Mloston, Grzegorz; Celeda, Malgorzata; Jasinski, Radomir; Heimgartner, Heinz (2018). Experimental and Computational Studies on Stepwise [3+2]-Cycloadditions of Diaryldiazomethanes with Electron-Deficient Dimethyl (E)- and (Z)-2,3-Dicyanobutenedioates. European Journal of Organic Chemistry:Epub ahead of print.

Abstract

Electron-deficient dimethyl (E)- and (Z)-2,3-dicyanobutenedioates (dimethyl dicyanofumarate and dicyanomaleate, respectively) react with diaryldiazomethanes at room temperature under spontaneous evolution of N2. The type of the products strongly depends on the structure of the diazo compound. Whereas diphenyldiazomethane and its bis(4-methoxy) derivative yield cyclopropanes, sterically crowded 5-diazo-5H-dibenzo[a,d]cycloheptane derivatives afford either the dimer of the carbene formed via N2 elimination or the adduct of the carbene onto the starting diazo compound. The course of the studied reactions is rationalized by stepwise mechanisms initiated by the formation of a C–N bond. A cascade of reactions leads to the corresponding cyclopropanes or to release of a carbene species. The formation of a pyrazole via [3+2]-cycloaddition (32CA) is observed only in reactions with (trimethyl- silyl)diazomethane, which behaves similar to the parent diazomethane. The proposed mechanisms were analyzed computationally using the DFT method.

Abstract

Electron-deficient dimethyl (E)- and (Z)-2,3-dicyanobutenedioates (dimethyl dicyanofumarate and dicyanomaleate, respectively) react with diaryldiazomethanes at room temperature under spontaneous evolution of N2. The type of the products strongly depends on the structure of the diazo compound. Whereas diphenyldiazomethane and its bis(4-methoxy) derivative yield cyclopropanes, sterically crowded 5-diazo-5H-dibenzo[a,d]cycloheptane derivatives afford either the dimer of the carbene formed via N2 elimination or the adduct of the carbene onto the starting diazo compound. The course of the studied reactions is rationalized by stepwise mechanisms initiated by the formation of a C–N bond. A cascade of reactions leads to the corresponding cyclopropanes or to release of a carbene species. The formation of a pyrazole via [3+2]-cycloaddition (32CA) is observed only in reactions with (trimethyl- silyl)diazomethane, which behaves similar to the parent diazomethane. The proposed mechanisms were analyzed computationally using the DFT method.

Statistics

Citations

Dimensions.ai Metrics

Altmetrics

Downloads

2 downloads since deposited on 30 Aug 2018
2 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:18 August 2018
Deposited On:30 Aug 2018 09:27
Last Modified:30 Aug 2018 09:30
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:1099-0690
OA Status:Closed
Publisher DOI:https://doi.org/10.1002/ejoc.201800837

Download