The first examples of a meta-benzannulation from the reaction of Fischer carbene complexes with alkynes

Journal of the American Chemical Society
Huan WangArnold L Rheingold

Abstract

The intramolecular benzannulations of carbene complexes with alkynes are examined where the alkyne is tethered to the alpha-carbon of the vinyl carbene complex. These reactions are sensitive to the length of the tether and to the nature of the solvent. With a tether length of 16 methylenes, the reaction occurs in the same fashion as the intermolecular reactions to give a p-cyclophane. With intermediate tether lengths (n = 10, 13), the reaction gives an additional p-cyclophane in which the two oxygen substituents are meta on the arene ring. This type of product is unprecedented from the reaction of carbene complexes and alkynes and is quite surprising because the formation of this product requires that the carbon-carbon bond between the alpha- and beta-carbons of the vinyl carbene complex is broken. A mechanism is proposed to account for this process which involves the crossed intramolecular [2 + 2] cycloaddition of the alkene and a ketene in a conjugated dienyl ketene to give a benzvalenone paddalane intermediate.

References


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Citations

Oct 3, 2008·Chemical Communications : Chem Comm·Miguel A SierraFernando P Cossío
Sep 7, 2017·Organic & Biomolecular Chemistry·Wangze SongWeiping Tang
Oct 2, 2015·Beilstein Journal of Organic Chemistry·Sambasivarao KothaGopalkrushna T Waghule
Nov 28, 2012·Angewandte Chemie·Alexander V PredeusWilliam D Wulff
Mar 18, 2008·The Journal of Organic Chemistry·Chenyi YiSilvio Decurtins
Aug 1, 2009·Chemical Reviews·Karl Heinz Dötz, Joachim Stendel
Oct 28, 2004·Journal of the American Chemical Society·Vijay Gopalsamuthiram, William D Wulff

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