Heterosubstituierte Acetylene, XXIX. „Onium”︁ ‐Umlagerungen zu disubstituierten Acetylenen: Die Synthese der In‐ diamine

Delavarenne, S.; Viehe, H. G.

doi:10.1002/cber.19701030424

Cited by 49 publications

(8 citation statements)

References 11 publications

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“…Bis(diethylamino)acetylene ( 1 ) is obtained by treating 2‐fluoro‐1,1‐dichloroethene or trichloroethene with N , N ‐disubstituted lithium amides and secondary amines 10. In 1 , the N−C≡C bond is cleaved by lithium in THF to give two lithium compounds (Et 2 NLi and Et 2 N−C≡CLi), which react with various electrophiles.…”

Section: Resultsmentioning

confidence: 99%

“…Melting points (uncorrected) were obtained on a Büchi apparatus, using capillaries that were filled under nitrogen and sealed. Bis(diethylamino)acetylene10 ( 1 ), ( i Pr 2 N) 2 BCl,29 1‐aryl‐2‐(trimethylstannyl)acetylenes30 3 , and chlorocatecholborane31 were prepared according to literature procedures. Bromo(dithiocatechol)borane and bromo(1,3,2‐benzothiaoxaborol), which have not been reported previously in the literature, were prepared by the reactions of dithiocatechol and 2‐hydroxythiophenol with excess BBr 3 .…”

Section: Methodsmentioning

confidence: 99%

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Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes

et al. 2004

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes

et al. 2004

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“…In marked contrast to the cyclic oxonium ylide 2 , it seems reasonable to assume that the corresponding cyclic sulfonium ylide 17 , would not establish an equilibrium with the free alkylidenecarbene 1 , given that no evidence for formation of the alkylidenecarbene-derived products was obtained when the reaction was carried out in tetrahydrothiophene (THT) instead of THF as a solvent. Thus, reaction of 7 with triethylamine in THT at 25 °C for 10 h afforded only sulfonium ylide-derived products, the sulfonium salt 18 (R = Bu; 87%) and the three-component coupling product 19a (R = Bu; 7%).…”

Section: Resultsmentioning

confidence: 99%

Evidence for Reversible Ylide Formation: Equilibrium between Free Alkylidenecarbenes and Ethereal Solvent−Alkylidenecarbene Complexes (Oxonium Ylides)

et al. 1996

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The free alkylidenecarbene, 2-butyl-1-hexenylidene 1 (R ) Bu), generated by triethylamine-induced R-elimination of 2-butyl-1-hexenyliodonium tetrafluoroborate 7 in tetrahydrofuran undergoes regioselective 1,5-C-H insertions, 1,2-shifts of the butyl group, and electrophilic attack on the tertiary amine followed by protonation to give the cyclopentene 8, the alkyne 9, and the vinylammonium salt 10, respectively. In addition to these free carbene-derived products, the reaction affords the three-component coupling product, the vinyl ether 11, produced through nucleophilic attack of tetrahydrofuran on 1 (R ) Bu) generating the oxonium ylide 2 (R ) Bu), followed by protonation with subsequent ring-opening of the resulting cyclic oxonium salt 15 (R ) Bu) by nucleophilic attack of triethylamine. Reactions were observed to be temperature dependent, as reflected in variations in the product profiles: decreasing the reaction temperature tended to decrease the yields of free alkylidenecarbene-derived products, i.e., cyclopentenes, alkynes, and vinylammonium salts, and to increase those of the vinyloxonium ylide-derived products, vinyl ethers. This temperature dependence is explained in terms of reversible oxonium ylide formation. No evidence was observed to suggest the existence of an equilibrium between the free alkylidenecarbene and the sulfonium ylide in the reaction in tetrahydrothiophene. These results are consistent with quantum calculations using the MOPAC 93 program.

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“…Whereas vinyldiazonium salt 3 could not be deprotonated by DABCO, we obviously succeeded in the case of 2-chloro-2methoxyphenyl-vinyl-diazonium salt 7, as indicated by the formation of chloro-methoxyphenyl acetylene 8. 2 This evidence suggests the generation of an intermediate diazoethene, which loses N 2 , and after a Fritch-Buttenberg-Wichel (F. B. W.) rearrangement 4 of the corresponding vinylidene, finally affords 8 (Scheme 2).…”

Section: 2-diethoxyvinylidene-triphenylphosphorane and 22-diethoxydia...mentioning

confidence: 99%

Roots: From carbenes to allenes and coordination polymers : Ever present never twice the same

Saalfrank

Maid

2005

Chem. Commun.

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The purpose of this Feature Article is to demonstrate that recognizing the similarities in different areas of chemistry allows the prediction of potential results in related fields. For instance, during our investigations of 2,2-diethoxyvinylidene-triphenylphosphorane we became interested in 2,2-diethoxydiazoethene. In order to obtain diazoethenes, we studied vinyl-diazonium salts and geminal vinyl-diazides as precursors. In the course of these investigations, we realized their synthetic potential to produce, via substituent-dependent 1,5-, 3,5-, or 1,5'-cyclization, a whole variety of heterocycles. However, more importantly, we became familiar with the chemistry of carbenes, which prompted an investigation of the carbene-like character of push-pull substituted allenes. Due to the ambiphilicity of their central carbon atom, they readily dimerized. Consequently, our strong interests in push-pull substituted allenes drew our attention to tetradonor substituted allenes, and as a result, we employed tetraethoxyallene as a synthetic equivalent to the fictitious malonic ester 1,1-/1,3-dianion synthon. This concept led to the synthesis of heterocumulenes and to the transallenation reaction to give allenecarboxanilides, which was further developed as a cumuhomologation for the synthesis of butatrienes via haloallenes from propargyl alcohols. The Diels-Alder reaction and intramolecular domino cyclization of multi-functional allenecarboxanilides yielded complex fused heteroarenes. Finally, the 1,5-cyclization of vinyl-azides, reported earlier, provided tetrazolylidene ligands, triggering our interest in supramolecular coordination chemistry, for example, the synthesis of one-, two- and three-dimensional coordination polymers.

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Heterosubstituierte Acetylene, XXIX. „Onium”︁ ‐Umlagerungen zu disubstituierten Acetylenen: Die Synthese der In‐ diamine

Cited by 49 publications

References 11 publications

Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes

Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes

Evidence for Reversible Ylide Formation: Equilibrium between Free Alkylidenecarbenes and Ethereal Solvent−Alkylidenecarbene Complexes (Oxonium Ylides)

Roots: From carbenes to allenes and coordination polymers : Ever present never twice the same

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