Synthesis of potentially antiviral cyclopropyl nucleosides

SUMMARY: Vinylcyclopropanes are important synthetic intermediates in organic chemistry and are mostly synthesized by the simultaneous introduction of the cyclopropane and the vinyl unit, e. g., by the reaction of trans-1,4-dihalobutenes with b -dicarbonyl compounds or the addition of carbenes to dienes. The polymerization of vinylcyclopropane itself results in vinyl polymers with predominantly 1,2-structural units. The radical polymerization of substituted vinylcyclopropanes results in polymers with mainly 1,5-ring-opened units, whereby radical stabilizing substituents or electron-withdrawing groups increase the radical polymerizability and the ring-opening ability. The vinylcyclopropanes undergo a radical copolymerization with other vinyl monomers, such as methacrylates, and, in comparison to the polymerization of these linear vinyl monomers, the vinylcyclopropanes show a significantly lower volume shrinkage during ring-opening polymerization. Hybrid vinylcyclopropanes are polymerized step-by-step under formation of reactive polymers or polymer networks. Multifunctional cross-linking vinylcyclopropanes can be used as new low-shrinking matrix monomers for photopolymerizable materials. In addition, the sol-gel process of trialkoxysilyl-functionalized vinylcyclopropanes affords low shrinking organic-inorganic nanocomposites.

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“…A simple method for the synthesis of 1,2,3-substituted cyclopropyl derivatives was developed by Cluet 54) (Scheme 7).…”

Section: Synthesis Of Vinylcyclopropanesmentioning

confidence: 99%

Synthesis and polymerization of vinylcyclopropanes

Moszner

Zeuner

Völkel

et al. 1999

Macromol. Chem. Phys.

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“…Cyclopropane moieties have been found in a wide range of natural and unnatural compounds that exhibit important biological activities and in an array of substances used as starting materials and intermediates in organic synthesis. − This has motivated a large number of research groups to develop new and wide-ranging methods to produce cyclopropanated products. − …”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Samarium (II) Carbenoid (ISmCH₂I) Promoted Cyclopropanation Reactions with Ethylene and the Effect of THF Solvent on the Reaction Pathways

2003

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A computational study of the cyclopropanation reactions of divalent samarium carbenoid ISmCH(2)I with ethylene is presented. The reaction proceeds through two competing pathways: methylene transfer and carbometalation. The ISmCH(2)I species was found to have a "samarium carbene complex" character with properties similar to previously investigated lithium carbenoids (LiCH(2)X where X = Cl, Br, I). The ISmCH(2)I carbenoid was found to be noticeably different in structure with more electrophilic character and higher chemical reactivity than the closely related classical Simmons-Smith (IZnCH(2)I) carbenoid. The effect of THF solvent was investigated by explicit coordination of the solvent THF molecules to the Sm (II) center in the carbenoid. The ISmCH(2)I/(THF)(n)() (where n = 0, 1, 2) carbenoid methylene transfer pathway barriers to reaction become systematically lower as more THF solvent is added (from 12.9 to 14.5 kcal/mol for no THF molecules to 8.8 to 10.7 kcal/mol for two THF molecules). In contrast, the reaction barriers for cyclopropanation via the carbometalation pathway remain high (>15 kcal/mol). The computational results are briefly compared to other carbenoid reactions and related species.

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“…Cyclopropane groups are observed in many natural and unnatural products possessing important biological activities and in a number of compounds used as starting materials and intermediates in organic synthesis. − Therefore, many research groups have discovered novel and diverse methods to make cyclopropanated products. − For instance, the reactions between diazoalkane and olefinic substrates assisted by transition metal com...…”

Section: Introductionmentioning

confidence: 99%

“…A variety of the Norrish−Yang reaction was recently found to be useful to produce cyclopropane products for some molecules − These are only a few examples of the various methods that have been developed over the years to produce cyclopropanated products. − …”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Investigation of the Remarkable Reactivity of Geminal Dizinc Carbenoids (RZn)₂CHI (R = Et or I) as Cyclopropanation Reagents with Olefins Compared to Mono Zinc Carbenoids RZnCHI₂, EtCHIZnR (R = Et or I)

2002

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Density functional theory calculations for the cyclopropanation reactions of several mono zinc carbenoids and their corresponding gem-dizinc carbenoids with ethylene are reported. The mono zinc carbenoids react with ethylene via an asynchronous attack on one CH2 group of ethylene with a relatively high barrier to reaction in the 20-25 kcal/mol range similar to other Simmons-Smith type carbenoids previously studied. In contrast, the gem-dizinc carbenoids react with ethylene via a synchronous attack on both CH2 groups of ethylene and substantially lower barriers to reaction (about 15 kcal/mol) compared to their corresponding mono zinc carbenoid. Both mono zinc and gem-dizinc carbenoid reactions can be accelerated by the addition of ZnI2 groups as a Lewis acid, and this lowers the barrier by another 1.0-5.1 kcal/mol and 0.0-5.5 kcal/mol, respectively, for addition of one ZnI2 group. Our results indicate that gem-dizinc carbenoids react with C=C bonds with significantly lower barriers to reaction and in a noticeably different manner than Simmons-Smith type mono zinc carbenoids. The three gem-dizinc carbenoids have a substantially larger positive charge distribution than those in the mono zinc carbenoids and, hence, a stronger electrophilic character for the gem-dizinc carbenoids.

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Synthesis of potentially antiviral cyclopropyl nucleosides

Cited by 17 publications

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Synthesis and polymerization of vinylcyclopropanes

Synthesis and polymerization of vinylcyclopropanes

Theoretical Study of Samarium (II) Carbenoid (ISmCH₂I) Promoted Cyclopropanation Reactions with Ethylene and the Effect of THF Solvent on the Reaction Pathways

Density Functional Theory Investigation of the Remarkable Reactivity of Geminal Dizinc Carbenoids (RZn)₂CHI (R = Et or I) as Cyclopropanation Reagents with Olefins Compared to Mono Zinc Carbenoids RZnCHI₂, EtCHIZnR (R = Et or I)

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Synthesis of potentially antiviral cyclopropyl nucleosides

Cited by 17 publications

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Synthesis and polymerization of vinylcyclopropanes

Synthesis and polymerization of vinylcyclopropanes

Theoretical Study of Samarium (II) Carbenoid (ISmCH2I) Promoted Cyclopropanation Reactions with Ethylene and the Effect of THF Solvent on the Reaction Pathways

Density Functional Theory Investigation of the Remarkable Reactivity of Geminal Dizinc Carbenoids (RZn)2CHI (R = Et or I) as Cyclopropanation Reagents with Olefins Compared to Mono Zinc Carbenoids RZnCHI2, EtCHIZnR (R = Et or I)

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Theoretical Study of Samarium (II) Carbenoid (ISmCH₂I) Promoted Cyclopropanation Reactions with Ethylene and the Effect of THF Solvent on the Reaction Pathways

Density Functional Theory Investigation of the Remarkable Reactivity of Geminal Dizinc Carbenoids (RZn)₂CHI (R = Et or I) as Cyclopropanation Reagents with Olefins Compared to Mono Zinc Carbenoids RZnCHI₂, EtCHIZnR (R = Et or I)