Synthesis of Ferrocenylbenzenes via Cp*RuCl-Catalyzed Partially Intramolecular Cyclotrimerization of Ferrocenylalkynes

Yamamoto, Yoshihiko; Kataoka, Hisashi; Kinpara, Keisuke; Nishiyama, Hisao; Itoh, Kenji

doi:10.2174/1570178053765258

Cited by 11 publications

(3 citation statements)

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“…[9] The yield only accounts for 10 % of the added alkyne, because the formation of 2 S is rather competitive even at ambient temperature as monitored by NMR spectroscopy. In spite of the importance of ferrocenylarenes, few reports dealt with the cyclotrimerization of HC C À Fc [10] because of the bulky ferrocenyl group. Three effective catalysts are [Co 2 (CO) 8 ], [11] TaCl 5 , [12] and cobaltocene; [9] however, they result in a mixture of 1,3,5-and 1,2,4-triferrocenylbenzenes.…”

Section: Resultsmentioning

confidence: 99%

Reactions of 16e CpCo Half‐Sandwich Complexes Containing a Chelating 1,2‐Dicarba‐closo‐dodecaborane‐1,2‐dichalcogenolate Ligand with Ethynylferrocene and Dimethyl Acetylenedicarboxylate

Peng

et al. 2008

Chemistry A European J

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The reaction of the 16e half-sandwich complex [CpCo(S2C2B10H10)] (1S; Cp: cyclopentadienyl) with ethynylferrocene in CH2Cl2 at ambient temperature leads to [CpCo(S2C2B10H9)-(CH2CFc)] (2S; Fc: ferrocenyl) and 1,2,4-triferrocenylbenzene. In 2S, B substitution occurs at the carborane cage in the position B3/B6 with the formation of a C-B bond. In the presence of the protic solvent MeOH, 2S loses a CpCo fragment to generate [(CH2CFc)(S2C2B10H9)] (3S). On the other hand, 2S can take a free CpCo fragment to form [(CpCo)2(S2C2B9H8)-(CHCFc)] (4S) containing a nido-C2B9 unit. In sharp contrast, [CpCo-(Se2C2B10H10)] (1Se) does not react with the alkyne in CH2Cl2, but in MeOH [(CHCFc)(Se2C2B10H10)] (5Se) is generated without the presence of a CpCo unit. The reaction of 1 with dimethyl acetylenedicarboxylate at ambient temperature leads to insertion compounds [CpCo(E2C2B10H10){(MeO2C)-C=C(CO2Me)}] (6S, E=S; 6 Se, E=Se). Upon heating, 6S rearranges to two geometrical isomers [CpCo(S2C2B10H9){(MeO2C)C=CH(CO2Me)}] (7S) and [CpCo(S2C2B10H9){(MeO2C)-CHC(CO2Me)}] (8S). In both, B-H functionalization takes place at the carborane cage in the position B3/B6, but 7S is a 16e complex with an olefinic unit in a Z configuration, and 8S is an 18e complex containing an alkyl B-CH group. Further treatment of 7 S with dimethyl acetylenedicarboxylate at ambient temperature affords two B-disubstituted complexes at the carborane cage in the positions of the B3 and B6 sites, that is, [CpCo(S2C2-B10H8){(MeO2C)C=CH(CO2Me)}2] (9S) and [CpCo(S2C2B10H8){(MeO2C)-CHC(CO2Me)}{(MeO2C)C=CH-(CO2Me)}] (10S). Compound 9S is a 16e complex with two olefinic units in E/E configurations, whereas 10S is an 18e species containing both an olefinic substituent and an alkyl B--CH unit. The reaction of 7S with methyl acetylenemonocarboxylate at ambient temperature leads to the sole 16e compound [CpCo(S2C2B10H8){CH=CH(CO2Me)}-{(MeO2C)C=CH(CO2Me)}] (11S). In contrast, 6Se does not rearrange. All new complexes 2S-4S, 5Se, 6Se, and 7S-11S were characterized by NMR spectroscopy (1H, 11B, 13C) and X-ray structural analyses were performed for 2S-4S, 5Se, 6Se, and 7S-9S.

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Section: Resultsmentioning

confidence: 99%

Reactions of 16e CpCo Half‐Sandwich Complexes Containing a Chelating 1,2‐Dicarba‐closo‐dodecaborane‐1,2‐dichalcogenolate Ligand with Ethynylferrocene and Dimethyl Acetylenedicarboxylate

Peng

et al. 2008

Chemistry A European J

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“…In this context, the [2 + 2 + 2] cyclocotrimerization of ferrocenylalkynes is a viable route to highly substituted ferrocenylbenzenes, although the control of regiochemistry and pair selectivity is a serious drawback [62]. Later, it is disclosed that the ruthenium complex, Cp*RuCl(cod), is also effective for similar reactions [64]. Among several catalysts they tested, RhCl(PPh 3 ) 3 and CoBr(PPh 3 ) 3 gave better results.…”

Section: Iii-2 Synthesis Of Artificial Functional Moleculesmentioning

confidence: 99%

“…Recently, the selective cyclocotrimerizations using 1,6-diynes and ferrocenylalkynes were achieved by Kotora, Štepni ∨ cka and co-workers as shown in Scheme 41 [63]. The rhodium catalyst was also able to convert alcohol 124 to ferrocenylbenzyl alcohol 125 in moderate yield (Scheme 42) [63], while the regioselective synthesis of bis(ferrocenyl)isobenzofuran derivative 127 was achieved by means of the ruthenium-catalyzed cycloaddition of ferrocenyldiyne 126 with 122 (Scheme 43) [64]. For example, the malonatederived diyne 121 (X = C(CO 2 Et) 2 ) was allowed to react with 1 equiv of ethynylferrocene 122 for 24-48 h at 20 ˚C in the presence of 10 mol % catalyst to afford the desired ferrocenylindan 123 (X = C(CO 2 Et) 2 ) in 57 and 70% yields.…”

Section: Iii-2 Synthesis Of Artificial Functional Moleculesmentioning

confidence: 99%

Recent Advances in Intramolecular Alkyne Cyclotrimerization and Its Applications

Yamamoto

2005

COC

Self Cite

255

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Transition-metal-catalyzed or -mediated intramolecular [2 + 2 + 2] alkyne cyclotrimerizations are one of the most efficient method to construct highly substituted arene frameworks in a single operation. The recent developments of novel catalyst systems as well as new strategies render the intramolecular cyclotrimerizations more and more attractive tools in practical organic synthesis. This review surveys most recent research works on the intramolecular alkyne cyclotrimerizations published from 2000 to 2004. The synthetic potential of the intramolecular alkyne cyclotrimerization is also discussed with respect to the recent applications to the synthesis of natural products and artificial functional molecules.

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Ruthenium‐Mediated [2 + 2 + 2] Cycloaddition

Yamamoto

2013

Transition‐Metal‐Mediated Aromatic Ring Construction

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Synthesis of Ferrocenylbenzenes via Cp*RuCl-Catalyzed Partially Intramolecular Cyclotrimerization of Ferrocenylalkynes

Cited by 11 publications

References 0 publications

Reactions of 16e CpCo Half‐Sandwich Complexes Containing a Chelating 1,2‐Dicarba‐closo‐dodecaborane‐1,2‐dichalcogenolate Ligand with Ethynylferrocene and Dimethyl Acetylenedicarboxylate

Reactions of 16e CpCo Half‐Sandwich Complexes Containing a Chelating 1,2‐Dicarba‐closo‐dodecaborane‐1,2‐dichalcogenolate Ligand with Ethynylferrocene and Dimethyl Acetylenedicarboxylate

Recent Advances in Intramolecular Alkyne Cyclotrimerization and Its Applications

Ruthenium‐Mediated [2 + 2 + 2] Cycloaddition

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