uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Oxaphospholes and Bisphospholes from Phosphinophosphonates and alpha,beta-Unsaturated Ketones
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
Show others and affiliations
2013 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 41, 13692-13704 p.Article in journal (Refereed) Published
Abstract [en]

The reaction of a {W(CO)(5)}-stabilized phosphinophosphonate 1, (CO)(5)WPH(Ph)P(O)(OEt)(2), with ethynyl- (2a-f) and diethynylketones (7-11, 18, and 19) in the presence of lithium diisopropylamide (LDA) is examined. Lithiated 1 undergoes nucleophilic attack in the Michael position of the acetylenic ketones, as long as this position is not sterically encumbered by bulky (iPr)(3)Si substituents. Reaction of all other monoacetylenic ketones with lithiated 1 results in the formation of 2,5-dihydro-1,2-oxaphospholes 3 and 4. When diacetylenic ketones are employed in the reaction, two very different product types can be isolated. If at least one (Me)(3)Si or (Et)(3)Si acetylene terminus is present, as in 7, 8, and 19, an anionic oxaphosphole intermediate can react further with a second equivalent of ketone to give cumulene-decorated oxaphospholes 14, 15, 24, and 25. Diacetylenic ketones 10 and 11, with two aromatic acetylene substituents, react with lithitated 1 to form exclusively ethenyl-bridged bisphospholes 16 and 17. Mechanisms that rationalize the formation of all heterocycles are presented and are supported by DFT calculations. Computational studies suggest that thermodynamic, as well as kinetic, considerations dictate the observed reactivity. The calculated reaction pathways reveal a number of almost isoenergetic intermediates that follow after ring opening of the initially formed oxadiphosphetane. Bisphosphole formation through a carbene intermediate G is greatly favored in the presence of phenyl substituents, whereas the formation of cumulene-decorated oxaphospholes is more exothermic for the trimethylsilyl-containing substrates. The pathway to the latter compounds contains a 1,3-shift of the group that stems from the acetylene terminus of the ketone substrates. For silyl substituents, the 1,3-shift proceeds along a smooth potential energy surface through a transition state that is characterized by a pentacoordinated silicon center. In contrast, a high-lying transition state TS(E-F)(R=Ph) of 37kcalmol(-1) is found when the substituent is a phenyl group, thus explaining the experimental observation that aryl-terminated diethynylketones 10 and 11 exclusively form bisphospholes 16 and 17.

Place, publisher, year, edition, pages
2013. Vol. 19, no 41, 13692-13704 p.
Keyword [en]
cumulenes, density functional calculations, domino reactions, phosphaorganic chemistry, reaction mechanisms
National Category
Natural Sciences
URN: urn:nbn:se:uu:diva-210179DOI: 10.1002/chem.201302014ISI: 000325135800015OAI: oai:DiVA.org:uu-210179DiVA: diva2:661611
Available from: 2013-11-04 Created: 2013-11-04 Last updated: 2013-11-04Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Arkhypchuk, Anna I.Orthaber, AndreasMihali, Viorica AlinaOtt, Sascha
By organisation
Molecular BiomimeticsStructural Chemistry
In the same journal
Chemistry - A European Journal
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 421 hits
ReferencesLink to record
Permanent link

Direct link