UZH-Logo

Maintenance Infos

Reactions of Diazomethanes with 5-Benzylidene-3-phenylrhodanine - A Computational Study


Khlebnikov, Alexander F; Seyfried, Martin S; Heimgartner, Heinz (2016). Reactions of Diazomethanes with 5-Benzylidene-3-phenylrhodanine - A Computational Study. Helvetica Chimica Acta, 99(2):110-115.

Abstract

It has been shown previously that the reaction of diazomethane with 5-benzylidene-3-phenylrhodanine (1) in THF at -20° occurs at the exocyclic C=C bond via cyclopropanation to give 3a and methylation to yield 4, respectively, whereas the corresponding reaction with phenyldiazomethane in toluene at 0° leads to the cyclopropane derivative 3b exclusively. Surprisingly, under similar conditions, no reaction was observed between 1 and diphenyldiazomethane, but the 2-diphenylmethylidene derivative 5 was formed in boiling toluene. In the present study, these results have been rationalized by calculations at the DFT B3LYP/6-31G(d) level using PCM solvent model. In the case of diazomethane, the formation of 3a occurs via initial Michael addition, whereas 4 is formed via [3 + 2] cycloaddition followed by N2 elimination and H-migration. The preferred pathway of the reaction of 1 with phenyldiazomethane is a [3 + 2] cycloaddition, subsequent N2 elimination and ring closure of an intermediate zwitterion to give 3b. Finally, the calculations show that the energetically most favorable reaction of 1 with diphenyldiazomethane is the initial formation of diphenylcarbene, which adds to the S-atom to give a thiocarbonyl ylide, followed by 1,3-dipolar electrocyclization and S-elimination.

Abstract

It has been shown previously that the reaction of diazomethane with 5-benzylidene-3-phenylrhodanine (1) in THF at -20° occurs at the exocyclic C=C bond via cyclopropanation to give 3a and methylation to yield 4, respectively, whereas the corresponding reaction with phenyldiazomethane in toluene at 0° leads to the cyclopropane derivative 3b exclusively. Surprisingly, under similar conditions, no reaction was observed between 1 and diphenyldiazomethane, but the 2-diphenylmethylidene derivative 5 was formed in boiling toluene. In the present study, these results have been rationalized by calculations at the DFT B3LYP/6-31G(d) level using PCM solvent model. In the case of diazomethane, the formation of 3a occurs via initial Michael addition, whereas 4 is formed via [3 + 2] cycloaddition followed by N2 elimination and H-migration. The preferred pathway of the reaction of 1 with phenyldiazomethane is a [3 + 2] cycloaddition, subsequent N2 elimination and ring closure of an intermediate zwitterion to give 3b. Finally, the calculations show that the energetically most favorable reaction of 1 with diphenyldiazomethane is the initial formation of diphenylcarbene, which adds to the S-atom to give a thiocarbonyl ylide, followed by 1,3-dipolar electrocyclization and S-elimination.

Altmetrics

Downloads

5 downloads since deposited on 23 Feb 2016
5 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:12 February 2016
Deposited On:23 Feb 2016 14:34
Last Modified:05 Apr 2016 20:08
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0018-019X
Funders:Russian Foundation for Basic Research (Grant No. 14-03-00187, Saint Petersburg State University (Grant No. 12.38.217.2015)
Publisher DOI:https://doi.org/10.1002/hlca.201500258

Download

[img]
Filetype: PDF - Registered users only
Size: 1MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations