Studies on the mechanism for stereoisomerization of 1-zirconacyclopent-3-yne compounds

Suzuki, Noriyuki; Nishimura, Kosuke; Ohara, Nozomu; Nishiura, Masayoshi; Masuyama, Yoshiro

doi:10.1016/j.jorganchem.2011.10.009

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…NMR data revealed a predominance of one stereoisomer of 8 whose isomerization could not be observed on the NMR timescale at room temperature. This is in sharp contrast to 1 , where the initially formed cis complex readily isomerized to the trans ‐isomer at room temperature 22. Although no stereochemical assignments have been made, we postulate that this easily isomerizable isomer bears the syn ‐form considering the results of compound 12 and 16 (vide infra).…”

Section: Resultsmentioning

confidence: 83%

Synthesis and Structure of Seven‐Membered Metallacycloalkynes

et al. 2012

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Seven-membered metallacycloalkyne compounds were synthesized. The reaction of the zirconocene-ethylene complex and (Z)-1,4-bis(trimethylsilyl)buta-1,2,3-triene gave a mixture of 1-zirconacyclopent-3-yne and 1-zirconacyclohept-3yne. In contrast, zirconocene-alkyne complexes, such as those of 1-(trimethylsilyl)prop-1-yne and diphenylacetylene, [a] 349 Scheme 4. Preparation of 1-zirconacyclohept-2-en-5-yne 12 and the byproducts.19 was not formed probably due to steric repulsions between the tetramethylcyclopentylidene moieties of 17 and the phenyl/cyclopentadienyl groups of the zirconium species.Scheme 5. Preparation of 1-zirconacyclohept-2-en-5-yne 16 from diphenylacetylene.Scheme 6. Reaction of zirconocene 15 with [5]cumulene compound.

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Section: Resultsmentioning

confidence: 83%

Synthesis and Structure of Seven‐Membered Metallacycloalkynes

et al. 2012

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“…Alternatively, 16 could be synthesized directly from ClCH 2 C≡CCH 2 Cl with two equivalents of Cp 2 ZrCl 2 and three equivalents of Mg, or from 14 with BEt 3 [46]. Two analogues 17 and 18 were produced similarly (Scheme 8) [38,47].…”

Section: Formation Of Alkyne-coordinated Complexesmentioning

confidence: 99%

Acetylenic Carbon-Containing Stable Five-Membered Metallacycles

2020

Catalysts

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Due to the linear property around an acetylenic carbon, the introduction of such an atom to a small cycle would result in high ring strain. Currently, the smallest isolated rings are five-membered, including metallacycloalkynes and metallapentalynes. Both types contain at least one unusual small bond angle around the acetylenic carbon, thus exhibiting abnormal reactivities. This feature article gives a comprehensive overview on these two kind complexes. The synthesis and reactivities are extensively described, the source of stability is presented, and the future prospect is discussed. The article aims to provide a better development for the chemical diversity of five-membered metallacycloalkynes and metallapentalynes.

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“…Thereafter, he taught and did research at Sophia University in Japan. He is involved in several works other than Pd-catalyzed and Sn(II)-mediated carbonyl allylation, namely: molybdenummediated/catalyzed reactions (Kurusu, Masuyama, Saito M & Saito S, 1986;Masuyama, Takahashi & Kurusu, 1984;Masuyama, Tsuhako & Kurusu 1981;Masuyama, Kurusu & Segawa, 1987a;Masuyama, Yamada & Kurusu, 1987b;Trost & Masuyama, 1984), tetrabromooxomolybdate complex-catalyzed oxidations , synthesis of some dinuclear metal complexes (Guidote et al, 2001a(Guidote et al, , 2001b, hydrodesulfurization of dibenzothiophene derivatives over metal catalysts (Saih et al, 2005), various syntheses other than allylations using tin as catalyst, such as aziridination and amination (Masuyama, Ohtsuka, Harima & Kurusu, 2006a), carbonyl propargylation (Masuyama, Yamazuki, Ohtsuka & Kurusu, 2006c), aldol condensations (Masuyama, Ohtsuka & Kondo, 2006b), cyclotrimerization of terminal alkynes (Masuyama, Miyazaki & Suzuki, 2013a), and aldehyde-alkyne couplings (Masuyama, Takamura & Suzuki, 2013b), synthesis and characterization of zirconium complexes (Podiyanachari et al, 2012;Suzuki et al, 2014Suzuki et al, , 2013Suzuki et al, , 2012Suzuki et al, , 2011bSuzuki et al, , 2011a and even the synthesis of an amino acid used for diagnostic studies (Usuki et al, 2012).…”

Section: About Yoshiro Masuyamamentioning

confidence: 99%

Palladium-Catalyzed Carbonyl Allylation Reactions Using Tin Chloride: A Mini-Review

Guidote

Baltazar

Yanela

et al. 2018

KIMIKA

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The treatment of allylic alcohols as synthons of carbanions for carbonyl allylation reactions in the presence of a Pd-SnCl2 system has been one of the most interesting and most useful developments demonstrated by Yoshiro Masuyama and co-workers in the field of organic synthesis. The reaction makes use of palladium as an effective catalyst and tin (II) chloride as a low-valent reducing agent which also effectively transforms the allylic group to a nucleophilic group. The organic, as well as organometallic, chemistry of how the transformations occur and how the metals take part in the reaction is of great interest. These could help allow for better optimization of reagents and solvents, for better control of the extent of reaction or yield of desired product, and for possible applications in other reaction systems. This review will focus primarily on the work of Yoshiro Masuyama and various co-workers on carbonyl allylation reactions making use of a Pd-SnCl2 system or substitutes thereof.

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Studies on the mechanism for stereoisomerization of 1-zirconacyclopent-3-yne compounds

Cited by 7 publications

References 37 publications

Synthesis and Structure of Seven‐Membered Metallacycloalkynes

Synthesis and Structure of Seven‐Membered Metallacycloalkynes

Acetylenic Carbon-Containing Stable Five-Membered Metallacycles

Palladium-Catalyzed Carbonyl Allylation Reactions Using Tin Chloride: A Mini-Review

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