Synthesis and Structure of the Smallest Cyclic Cumulene; Reaction of 1,3‐Diynes with Zirconocene Complexes

Rosenthal, Uwe; Ohff, Andreas; Baumann, Wolfgang; Kempe, Rhett; Tillack, Annegret; Burlakov, Vladimir V.

doi:10.1002/anie.199416051

Cited by 134 publications

(79 citation statements)

References 13 publications

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“…The central C(2)−C (3) , which is consistent with the assumption of the involvement of the C(2)−C(3) bond in the interaction with the zirconium center.…”

Section: ■ Results and Discussionsupporting

confidence: 64%

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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“…The central C(2)−C (3) , which is consistent with the assumption of the involvement of the C(2)−C(3) bond in the interaction with the zirconium center.…”

Section: ■ Results and Discussionsupporting

confidence: 64%

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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“…We also reported a simple and versatile preparative method for ''non-substituted'' 1-zirconacyclopent-3-ynes (1c-d: R = H) and showed their reactivity [13][14][15][16]. Five-membered metallacyclocumulenes reported by Rosenthal and coworkers showed similar structure and reactivity to metallacyclopentynes [17][18][19][20]. They have prepared a variety of zirconacyclocumulenes as well as titanacyclocumulenes and extensively studied their reactivity, although a hafnium analogue has not been reported.…”

Section: Introductionmentioning

confidence: 96%

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Suzuki

Watanabe

Yoshida

et al. 2006

Journal of Organometallic Chemistry

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“…This methodology realized the synthesis of stable fivemembered metallacyclotrienes (ii) [18][19][20], as well as metallacycloalkynes (iii) [21][22][23][24], which have been thought to be highly reactive and unisolable. According to these protocols one must consider that 1,3-enynes would be possible starting compound for cycloallenes (iv, Scheme 1), as predicted by N. SUZUKI et al…”

Section: Straightforward Synthesis Of Unsaturated Metallacyclesmentioning

confidence: 99%

Straightforward synthesis of five-membered metallacycloallenes: 1-Zirconacyclopenta-2,3-diene compounds derived from 1,3-enynes

Suzuki

Shimura

Sakaguchi

et al. 2011

Pure and Applied Chemistry

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A five-membered metallacycloallene complex, 1-zirconacyclopenta-2,3-diene, was prepared from low-valent zirconocene and 2,4-bis(trimethylsilyl)but-1-en-3-yne. The complex reacted with carbonyl compounds to afford alkynyl alcohols after hydrolysis via C=O insertion into Zr-C bond. Similarly, nitriles inserted into the Zr-C bond to give the corresponding ketones after hydrolysis. The insertion of C=O and CN selectively took place at zirconium-sp 3 carbon of the metallacycle. nium.Recently, we and Erker's group independently reported stable five-membered cycloallenes, 1-metallacyclopenta-2,3-diene compounds (Fig. 2) [7][8][9][10][11][12]. These complexes are stable at room temperature (rt). It should be noted that replacement of one carbon atom with a transition metal made the strained compounds much more stable, and it must be interesting to study their reactivity. The fivemembered zirconacycloallene 1 was synthesized by transformation of a conjugated 1-zirconacyclopent-3-yne complex. The 1-zircona-and 1-hafnacyclopenta-2,3-dienes 2 were prepared from the corresponding bis(alkynyl)metallocenes via 1,1-hydroboration. The preparative methods of these complexes, however, were specific and unsuitable for large-scale synthesis. Therefore, more versatile synthetic routes have been desired in order to study the reactivity of five-membered metallacycloallenes. Bertrand and co-workers recently reported several bent allene compounds [13][14][15], including small cycloallenes. These compounds are of interest in relation to the metallacycloallenes, although the allene character of these is yet controversial [16,17]. Straightforward synthesis of unsaturated metallacyclesFor the syntheses of metallacyclic compounds such as 1-metallacyclpent-3-enes, 1-metallacyclopenta-2,3,4-trienes, and 1-metallacyclopent-3-ynes, low-valent metallocenes and 1,3-dienes, 1,3-diynes, and 1,2,3-trienes are employed (i-iii, Scheme 1) [8]. This methodology realized the synthesis of stable fivemembered metallacyclotrienes (ii) [18][19][20], as well as metallacycloalkynes (iii) [21][22][23][24], which have been thought to be highly reactive and unisolable. According to these protocols one must consider that 1,3-enynes would be possible starting compound for cycloallenes (iv, Scheme 1), as predicted by N. SUZUKI et al.

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Synthesis and Structure of the Smallest Cyclic Cumulene; Reaction of 1,3‐Diynes with Zirconocene Complexes

Cited by 134 publications

References 13 publications

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

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

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Straightforward synthesis of five-membered metallacycloallenes: 1-Zirconacyclopenta-2,3-diene compounds derived from 1,3-enynes

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