Cyclopropanation of C60 via a fischer carbene complex

Merlic, Craig A.; Bendorf, Holly D.

doi:10.1016/0040-4039(94)88503-6

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…As discussed in the Introduction section, addition of carbene species to C 60 is one of the most extensively studied fullerene reactions and has become a versatile tool for the synthesis of fullerene adducts with methanofullerene scaffolds . For example, Merlic and Bendorf synthesized their functional methanofullerene by the cyclopropanation reaction between C 60 and a transition metal carbene complex . In our system, the tungsten carbene species at the ends of the growing polyacetylene chains may also undergo the same cyclopropanation reaction with C 60 , giving polyacetylene-functionalized methanofullerenes (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

Tang

Lam

et al. 2000

Chem. Mater.

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While polymerizations of 1-phenyl-1-propyne (PP) and 1-phenyl-1-butyne (PB) initiated by WCl 6 -Ph 4 Sn at room temperature yield small amounts of polymers (0.05-5.3%) with low molecular weights (M n 8000-15000) and high polydispersity indexes (PDI up to 109), addition of C 60 into the initiator mixture dramatically boosts its catalytic activity, producing polymers with high M n s (up to 171 000) and low PDIs (down to 2.2) in high yields (up to 99.5%). The resultant polymers are soluble, stable, and film-forming. GPC, IR, NMR, UV, and XRD analyses reveal that the polymers consist of polyacetylene chains and covalently bound C 60 cages (up to 9.1 wt %). Whereas photoluminescence of C 60 -containing polyPPs is faint, C 60 -containing polyPBs emit strong blue light (λ max ) 456 nm) readily observable with the naked eye under normal laboratory lighting. Compared with the parent C 60 , both two groups of the fullerene polyacetylenes show better optical limiting performance, and their THF solutions, with higher linear transmittance, attenuate the power of intense 532 nm optical pulses to lower saturation fluence.

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Section: Resultsmentioning

confidence: 99%

C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

Tang

Lam

et al. 2000

Chem. Mater.

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“…58 Methyl(methoxymethylene)Cr(CO) 5 has successfully been used to cyclopropanate fullerene C 60 . 59 A single isomer of the methanofullerene from cyclopropanation of a 6,6 ring junction was obtained in 20% to >50% yields.…”

Section: A [2+1] Metal-assisted Cycloaddition Reactionsmentioning

confidence: 99%

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

1997

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“…Thus, Wienand and Reissig have demonstrated that α,β-unsaturated lactones that cannot reach a cis conformation between the CC and CO bonds fail to undergo cyclopropanation with chromium carbene complexes 4c. In a similar way, only dienes with a readily accessible s - cis conformation can participate in this reaction, as reported by Harvey and Lund 8a…”

Section: Referencesmentioning

confidence: 73%

“…This reaction has been thoroughly studied not only for theoretical purposes, but more importantly also as a powerful method to access donor−acceptor cyclopropanes, compounds that have gained attention because of their high potential to serve as versatile intermediates . The cyclopropanation reaction was first reported for electron-poor , and, to a much lesser extent, electron-rich alkenes, and later it was extended to electron-poor, 4f, electron-rich, and unfunctionalized 1,3-dienes . Significantly, studies carried out recently in our laboratory showed for the first time that simple alkenes are capable of undergoing efficiently the intermolecular cyclopropanation reaction. , …”

Section: Introductionmentioning

confidence: 99%

Diastereo- and Enantioselective Cyclopropanation with Chromium Fischer Carbene Complexes: Alkenyl Oxazolines as Useful Achiral and Chiral Substrates

et al. 2001

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The cyclopropanation reaction of chromium Fischer carbene complexes with alkenyl oxazolines has been studied in both racemic and enantioselective fashions. The oxazolinyl group acts as both electron-acceptor substituent and chiral auxiliary. Achiral (4,4-dimethyloxazolin-2-yl)alkenes derived from trans-crotonic and trans-cinnamic acids 2a,b undergo the cyclopropanation reaction to give 4a-d,g with excellent diastereoselectivity (trans/cis ratio between 93:7 and >97:3), while those derived from acrylic and metacrylic acids 2c,d give the cyclopropanes 4e,f,h with much lower selectivity (trans/cis ratio between 68:32 and 83:17). The homogeneous catalytic hydrogenolysis of 4 leads in a selective manner to 5 or 6, depending on the nature of the R3 substituent. The removal of the oxazoline moiety is achieved by carboxybenzylation/hydrolysis and ester reduction, yielding monoprotected 1,4- and 1,3-diols 9 and 11, respectively. The alkenes derived from enantiopure (S)-valinol and (S)-tert-leucinol 3 led to cyclopropanes trans-12 with high relative and absolute stereocontrol. Using tert-leucinol as the auxiliary permits attaining total facial stereoselectivity (>98% ee). Reductive cleavage of the cyclopropane ring and removal of the auxiliary afford the enriched alcohols (3S,4S)-9 and (S)-11. The stereochemical outcome of the cyclopropanation reaction is rationalized by a trans approach of the s-cis conformer of the alkenyl oxazoline to the carbene complex involving the less hindered face of the oxazoline auxiliary and the re-face of the carbene complex.

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Cyclopropanation of C60 via a fischer carbene complex

Cited by 15 publications

References 27 publications

C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

Diastereo- and Enantioselective Cyclopropanation with Chromium Fischer Carbene Complexes: Alkenyl Oxazolines as Useful Achiral and Chiral Substrates

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Cyclopropanation of C60 via a fischer carbene complex

Cited by 15 publications

References 27 publications

C60-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

C60-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

Diastereo- and Enantioselective Cyclopropanation with Chromium Fischer Carbene Complexes: Alkenyl Oxazolines as Useful Achiral and Chiral Substrates

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C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting

C₆₀-Containing Poly(1-phenyl-1-alkynes): Synthesis, Light Emission, and Optical Limiting