Synthesis of a highly strained permethylenated cycloocta-1,5-diyne derivative by acid-catalysed thermal rearrangement

Kammermeier, Stefan; Siemsen, Peter; Seiler, Paul; Diederich, François; Tykwinski, Rik R.

doi:10.1039/a802927j

Cited by 12 publications

(9 citation statements)

References 17 publications

(6 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…172 The highly strained, diastereomeric products were isolated as an inseparable 2:1 mixture that showed surprisingly high kinetic and thermal stability. The structure of 212 could only be elucidated by X-ray analysis, which showed that the internal bond angles about the sp-hybridized carbons were significantly bent (157.4°) from the optimum of 180°.…”

Section: Expanded Radialenes With Acetylene Spacersmentioning

confidence: 99%

Oligomeric and Polymeric Systems with a Cross-conjugated π-Framework

2006

Self Cite

View full text Add to dashboard Cite

Section: Expanded Radialenes With Acetylene Spacersmentioning

confidence: 99%

Oligomeric and Polymeric Systems with a Cross-conjugated π-Framework

2006

Self Cite

View full text Add to dashboard Cite

“…2) is most similar to that of 10, reported by Diederich and coworkers. 25 Compound 5 also shares structural similarities with cyclooctadiyne 11, 26 as well as annulenes 12 27,28 and 13. 29 The acetylene units of 5 are significantly bent at angles of 156.81 and 156.91, which are in the same range as the values determined for molecules 10-12 (155.3-159.31).…”

Section: View Article Onlinementioning

confidence: 95%

Thermal dimerization of [n]cumulenes (n = 5, 7, 9)

et al. 2015

Self Cite

View full text Add to dashboard Cite

The thermal dimerization of three [n]cumulenes (n = 5, 7, and 9) has been investigated, and a common reactivity pattern is observed that gives radialenes and expanded radialenes through regioselective cycloaddition reactions; all three products are characterized using X-ray crystallography.Cycloaddition reactions of polyynes have been used to create conjugated molecules that are otherwise difficult to obtain, and the regioselectivity of these reactions can often be controlled by the electronic nature of endcapping groups. 1-3 On the other hand, this same level of control has not yet been achieved for reactions for the sp-carbon chain of long [n]cumulenes (n Z 5). 4 There have been a handful of reports in which [5]cumulenes react with electron-poor olefins or alkynes, but the regiochemistry of cycloaddition reactions is difficult to predict. 5-8 Dimerization reactions under thermal, photochemical, or metal-catalysed conditions that give cyclic oligoynes or radialenes are also known. 9 The regiochemistry observed for these cycloaddition reactions has been typically attributed to either steric requirements or to the electronic structure of endcapping groups. [10][11][12][13][14] 12 and the regiochemical outcome of these reactions centers on the reaction at either the b-or g-bond, and is dependent on the size and electronic makeup of the end groups. The reactivity of longer ''odd'' [n]cumulenes (i.e., n = 7 or 9) in cycloaddition reactions has not, to our knowledge, been reported to date.We describe herein the dimerization of [n]cumulenes, including the first reported reactions of [7]-and [9]cumulenes. These transformations follow a similar reactivity pattern, and the products provide a unique series of expanded radialenes that have been characterized by X-ray crystallography.Intrigued by the formation of 3 from [5]Ph as reported by Kawamura and coworkers, the thermal reaction of [5]tBuPh, recently synthesized in our laboratory, 18 was examined. After heating in toluene at reflux for 4 d (Scheme 2), the crude reaction mixture showed many products (by TLC analysis). The main product could be isolated by flash chromatography on silica gel, although NMR spectroscopy indicated the presence of several compounds. On the other hand, mass spectrometry showed a signal consistent with the mass expected for a dimer of

show abstract

“…Derivatives of tetraethynylated ethane 10 (Figure 2) were obtained by alkynylation of 1,5-diyne-3,4-dione 50, affording the diastereoisomeric diols meso-51 and ( )-51 (Scheme 13). 31 Next, meso-51 was converted into orthoester 52, and the SiMe 3 protecting groups were subsequently removed. Orthoesters such as 52 undergo acidcatalyzed thermolysis under formation of the corresponding TEE derivatives.…”

Section: Polyethynylated Ethanes and Methanesmentioning

confidence: 99%