Diverse Reactivity of Zirconacyclocumulenes Derived from Coupling of Benzynezirconocenes with 1,3‐Butadiynes towards Acyl Cyanides: Synthesis of Indeno[2,1‐<i>b</i>]pyrroles or [3]Cumulenones

Fu, Xiang; Chen, Jingjin; Li, Guangyu; Liu, Yuanhong

doi:10.1002/anie.200900951

Cited by 69 publications

(17 citation statements)

References 53 publications

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“…We also preparedt hree representatives (compounds 6h-j)o ft he indeno[1,2-b]pyrrole framework, which is almostneglected in the literature. [39] After verifyingi naseparate experiment that the intermediate a-iodoketones could be prepared under mechanochemical conditions by treatment of the corresponding ketone with N-iodosuccinimide in the presence of toluenesulfonic acid (see the Supporting Information for further details), we studied the HSVM-promoted telescopingo ft he iodoketone synthesis withaH antzsch-like reaction to furnish fused pyrrole derivatives. As summarized in Scheme 8a nd Ta ble 5( methodB), this one-pot process was much more efficient than the conventional one, and afforded the previously mentioned benzo-[g]indoles 6a-g,a nd also the indeno[1,2-b]pyrroles 6h-j,i n yields above 80 %i na ll cases, in spite of comprising one more reactiont han the conventional method (entries 1-10).…”

Section: Resultsmentioning

confidence: 99%

Three‐Component Synthesis of Pyrrole‐Related Nitrogen Heterocycles by a Hantzsch‐Type Process: Comparison between Conventional and High‐Speed Vibration Milling Conditions

et al. 2016

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The use of solvent-free, high-speed vibration milling conditions has allowed the development of ao ne-pot telescoped process for the synthesis of pyrroles starting from ketones, primary amines, and b-dicarbonyl compounds and comprising an initial a-iodination followed by an in situ three-component Hantzsch-type reaction. This methodw as compared with as olution-based protocol from a-iodoketones, primary amines,a nd b-dicarbonyl compounds. Although both protocols were far more general than previous Hantzsch-type pyrrole syntheses, the mechanochemical methodw as superior in that it afforded considerably higher yields in spite of comprising an additional step. The stereochemicali ntegrity of the pyrroles obtained from chiral aaminoesters wasm aintained. This solvent-free method was also used for the efficient preparationo fter-a nd quater-aryl/ heteroaryl frameworks containing two pyrrole units and avariety of fused pyrrole systems, including benzo[g]indoles, indeno[1,2-b]pyrroles, indoles,and homoindoles.

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Section: Resultsmentioning

confidence: 99%

Three‐Component Synthesis of Pyrrole‐Related Nitrogen Heterocycles by a Hantzsch‐Type Process: Comparison between Conventional and High‐Speed Vibration Milling Conditions

et al. 2016

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“…The results indicated that a CN group reacts preferentially with zirconacycle 2 / 3 at the initial step. The reaction pattern is quite different compared with that of the reactions of aroyl cyanides with seven‐membered zirconacyclocumulenes, which were prepared by coupling of benzynezirconocene with butadiynes 7c. In those reactions, a carbonyl group reacted preferentially with a propargyl zirconium moiety.…”

Section: Methodsmentioning

confidence: 96%

“…7a An S E 2′‐type addition of the CN group of carbamoyl cyanides to the less hindered propargyl zirconium moiety in complex 2 takes place to deliver an azazirconacyclocumulene 8 , which might isomerize to azazirconacyclopentadiene 10 ; however, we still cannot exclude the reaction pathway for 10 involving direct insertion of a cyano group into the ZrC

_{sp^{2}}

bond close to the R 1 group of 2 17. As a minor reaction pathway, addition of the CO group of carbamoyl cyanides to zirconacycle 2 / 3 affords either cyano‐substituted oxazirconacycle 9 or 11 ; hydrolysis of 11 gives enynyl amide 5 through elimination of a cyano group 7c. Attack of the nitrogen lone pair in intermediate 10 to the CN moiety of a second molecule of carbamoyl cyanide followed by intramolecular nucleophilic addition provides fused oxirane intermediate 13 ;18 ring opening of the oxirane by the electron‐rich N ‐phenyl ring leads to intermediate 14 , CC bond fragmentation followed by a 1,3‐hydrogen shift furnishes the final product 4 .…”

Section: Methodsmentioning

confidence: 99%

Unexpected Zirconium‐Mediated Multicomponent Reactions of Conjugated 1,3‐Butadiynes and Monoynes with Acyl Cyanide Derivatives

You

Liu

2012

Chemistry A European J

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“…Organometallics Article this complex with HCl in dioxane at 22°C affords Cp 2 ZrCl 2 and 1,4,5,8-tetra(trimethylsilyl)octa-3,5-diene-1,7-diyne (9).…”

Section: Methodsmentioning

confidence: 98%

Thermal Isomerization of the Buchwald Seven-Membered Zirconacyclocumulene and Its Interaction with Acetylenes. Synthesis and Structures of Novel Seven-Membered Zirconacyclocumulene Complexes

et al. 2015

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On prolonged heating of the Buchwald seven-membered zirconacyclocumulene Cp 2 Zr[η 4 -Me 3 SiC 4 (SiMe 3 )− C(C 2 SiMe 3 )CSiMe 3 ] (1) in toluene at 100 °C, the isomerization of 1 takes place with the formation of a seven-membered zirconacyclocumulene complex, Cp 2 Zr[η 4 -Me 3 SiC 4 (SiMe 3 )−C(SiMe 3 )C(C 2 SiMe 3 )] (8), containing the Me 3 SiCC group in α-position and the SiMe 3 group in β-position with respect to the Zr atom. A remarkable peculiarity of complex 8 is its ability to undergo a rapid degenerate rearrangement at room temperature in toluene solution, as a result of which only two rather than four singlets of the Me 3 Si groups are observed in the 1 H NMR spectrum of 8 under such conditions. At temperatures below 200 K, the rate of this rearrangement decreases and, as a consequence, the 1 H NMR spectrum of 8 acquires the normal view. If 1 is heated at 100 °C in the presence of acetylenes such as 1,4-bis(tert-butyl)butadiyne ( t BuCC−CC t Bu) and tolane, the corresponding seven-membered zirconacyclocumulenes, viz., Cp 2 Zr[η 4 -t BuC 4 ( t Bu)−C(C 2 SiMe 3 )CSiMe 3 ] ( 7) and Cp 2 Zr[η 4 -Me 3 SiC 4 (SiMe 3 )−C(Ph)CPh] (14), are formed along with free Me 3 SiCC−CCSiMe 3 . The interaction of 1 with 1,4diphenylbutadiyne (PhCC−CCPh) at 100 °C leads to the formation of a mixture of products, from which a zirconacyclopentadiene metallacycle, Cp 2 Zr[η 2 -PhCC(C 2 Ph)−C(C 2 Ph)CPh] (10), as well as seven-membered zirconacyclocumulenes Cp 2 Zr[η 4 -PhC 4 (Ph)−C(C 2 SiMe 3 )CSiMe 3 ] (11), Cp 2 Zr[η 4 -Me 3 SiC 4 (SiMe 3 )−C(C 2 Ph)CPh] (12), and Cp 2 Zr[η 4 -PhC 4 (Ph)−C(C 2 Ph)CPh] (13) were isolated. The structures of 8, 9, 10, 12, and 14 have been established by X-ray crystallography. The mechanism of the reactions found is discussed.

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Diverse Reactivity of Zirconacyclocumulenes Derived from Coupling of Benzynezirconocenes with 1,3‐Butadiynes towards Acyl Cyanides: Synthesis of Indeno[2,1‐b]pyrroles or [3]Cumulenones

Cited by 69 publications

References 53 publications

Three‐Component Synthesis of Pyrrole‐Related Nitrogen Heterocycles by a Hantzsch‐Type Process: Comparison between Conventional and High‐Speed Vibration Milling Conditions

Three‐Component Synthesis of Pyrrole‐Related Nitrogen Heterocycles by a Hantzsch‐Type Process: Comparison between Conventional and High‐Speed Vibration Milling Conditions

Unexpected Zirconium‐Mediated Multicomponent Reactions of Conjugated 1,3‐Butadiynes and Monoynes with Acyl Cyanide Derivatives

Thermal Isomerization of the Buchwald Seven-Membered Zirconacyclocumulene and Its Interaction with Acetylenes. Synthesis and Structures of Novel Seven-Membered Zirconacyclocumulene Complexes

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