Metallacycle Transfer from Zirconium to Main Group Elements: A Versatile Synthesis of Heterocycles

Fagan, Paul J.; Nugent, William A.; Calabrese, Joseph C.

doi:10.1021/ja00084a031

Cited by 357 publications

(173 citation statements)

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“…(27) Similarly, metallocene complexes of o-benzyne add to alkenes or alkynes, yielding 1-metallaindans and 1-metallaindenes, respectively (283). The zirconacyclopentadienes formed from the dimerization of alkynes are convenient synthons for phospholes, siloles, and germoles (284 …”

Section: Coupling Of Alkenes and Alkynes The Highly Reactive [Cp 2 Zr]mentioning

confidence: 99%

Metallocenes

Kuhlman¹

2016

Encyclopedia of Polymer Science and Technology

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Once narrowly defined as metal complexes of precise chemical formula (η 5 ‐C 5 H 5 ) 2 M, the word “metallocene” has evolved to represent a versatile class of polymerization technology that is slowly but significantly reshaping the polyolefin industry. Metallocene catalysts enable production of polyethylenes with narrow molecular weight and composition distributions, efficient incorporation of standard and nonstandard comonomers, an excellent spectrum of tacticity control in poly‐α‐olefins, and remarkable adaptability enabled by accumulated scientific endeavors relating ligand designs to polymer microstructures. Olefin polymerization is reviewed in some detail with emphasis on commercially relevant technologies, and a brief commercial overview is included. Nonpolymerization catalysis and (co)polymerization of functional monomers are also briefly summarized.

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Section: Coupling Of Alkenes and Alkynes The Highly Reactive [Cp 2 Zr]mentioning

confidence: 99%

Metallocenes

Kuhlman¹

2016

Encyclopedia of Polymer Science and Technology

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“…Further, we envision that this zirconacycle could be easily replaced by other heterocycles like phosphole, silole, germole, and so on. 8 Being encouraged by the reactivity of mono-ZCP 2a, we became interested in exploring similar reactions of di-ZCP 2b and tri-ZCP 2c (Figure 1). Protonation of di-and tri-ZCP produced multiple butadiene unit connected oligothiophene derivatives 3b and 3c respectively.…”

Section: Di-zcp 2bmentioning

confidence: 99%

Synthesis of Co-oligomers of Thiophene Derivatives from Oligoynes via Zirconacyclopentadiene

Payra¹,

Song²,

Kanno³

et al. 2011

Chemistry Letters

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For the formation of oligothiophenes or thiophene cooligomers, a preconnected method using zirconacyclopentadienes was demonstrated. Oligoynes of 4,4-bis(butoxymethyl)-1,6-heptadiyne linked through bithiophene were prepared where all components and diyne moieties were connected in advance before converting to zirconacyclopentadiene-containing precursors. Treatment of the reactive zirconacyclopentadienes in the preconnected precursors with acid, dimethyl acetylenedicarboxylate or sulfur monochloride afforded different oligothiophenes or thiophene co-oligomer derivatives.Oligomers of thiophene or co-oligomers of thiophene with other aromatic components have attracted much attention in relevance to electronic organic materials.1 Synthetic methodology of these oligomers or co-oligomers is an interesting topic. The most general conventional method is the connection of separate components in the presence of a catalytic or equivalent amount of metal compounds as shown in Scheme 1.2 Previously our group and others have demonstrated a Zr-mediated method which involves the conversion of the zirconacyclopentadiene moiety in the precursors into some component as shown in Scheme 1. 3 We have reported Ni-catalyzed polymerization of dibromoterphenyl units. 3a The dibromoterphenyl unit was prepared by this zirconium-mediated method. For the formation of the phenylene copolymers, Tilley and co-workers have reported a method via zirconium-containing phenylene precursors which were prepared by coupling of phenyl-bridged diyne units on zirconium (Scheme 2).3b Herein, we would like to report a novel method for preparation of zirconium-containing precursors using a preconnected method (Scheme 2) for constructing oligomers of thiophene or co-oligomers of thiophene and other conjugated fragments. The preconnected method helped to produce a welldefined conjugated backbone with complete regioselectivity of zirconacyclopentadienes. This is in sharp contrast to a coupling method on zirconium which gives a mixture of several components and regioisomers.Preconnected oligodiynes were prepared by the Sonogashira Hagihara coupling of a terminal diyne and bromo bithiophene. 2,2¤-Bithiophene was chosen as an oligothiophene and 4,4-bis(butoxymethyl)-1,6-heptadiyne as a terminal diyne unit. By careful control of the equivalent ratio of bromo substrate and diyne, oligodiyne 1a, 1b, and 1c were prepared in 83%, 85%, and 64% yields, respectively (Scheme 3). 4

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“…Symmetrical phosphole-derivatives 2.1.1. Synthesis 2,5-Di(heteroaryl)phospholes 3 (Scheme 1) were prepared via the 'Fagan-Nugent method', a general and efficient organometallic route to phosphole moieties [5]. The intramolecular oxidative coupling of functionalised 1,7-diynes 1 (Scheme 1), possessing a (CH 2 ) 4 spacer in order to obtain the desired 2,5-substitution pattern, with 'zirconocene' provides the corresponding zirconacyclopentadienes 2 [6].…”

Section: Co-oligomers Containing Phosphole Ringmentioning

confidence: 99%