Conglomerate crystallization in organic compounds II. The conformation, configuration, and spontaneous resolution of 1-phenyl-2-cyano-cyclopropane

Draux, Madelein; Bernal, Ivan; Fuchs, Richard

doi:10.1007/bf00676623

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…In another contribution from this group, we pointed out that the effect of the phenyl ring alone on oxirane rings seems to be anomalous [14] in that the values of the asymmetry parameters derived forp-nitrophenyl styrene oxide do not agree with those derived from phenylcyano-oxiranes. Therefore, we have undertaken an X-ray study on the title compound, which is a relatively simple, solid, unhindered compound which should permit straightforward evaluation of the inherent stereochemical preferences for the relative conformation of the phenyl ring with respect to the C--C--C angle at the point of substitution of the cyclopropane ring.…”

Section: ~Troductionmentioning

confidence: 86%

“…The cyclopropane ring itself has an average bond length of 1.489(3) ,~,, which is in the range reported by Allen [6a] for phenyl-substituted cyclopropanes (low by -0.15 A). This slightly low value might, as in the case of oxiranes [14], be related to the bisected position of the phenyl; at this position, the substituent 7r system has the greatest overlap with the occupied 3e' orbital of cyclopropane. For r-acceptor substituents, it has the effect 281 of shortening the distal cyclopropane bond by an amount ds while lengthening both vicinal bonds by an amount ds/2 with respect to the average bond length [6].…”

Section: ~Troductionmentioning

confidence: 94%

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Crystal structures of phenyl-substituted cyclopropanes. IV. the crystal structure (at 21‡C and −100‡C) and the phenyl ring conformation in 4-cyclopropylacetanilide

et al. 1997

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The crystal structure of 4-cyclopropylacetanilide was investigated at room temperature (21 ~ and at -100~ in order to determine the orientation of the phenyl ring with respect to the cyclopropane moiety and the effect of this substituent on the stereochemistry of the three-membered ring. The compound was chosen because it is one of the few species containing a simple phenyl ring as the sole cyclopropane ring substituent and whose crystals are suitable for X-ray diffraction at room temperature. The substance crystallizes in space group P21/c at either temperature (no phase transitions) with cell constants: (at 21~ a = 9.725(2), b = 10.934(3), and c = 9.636(2) .A., ~ = 106.13(1)~ V = 984.21 ~3 and d(calc; z = 4) = 1.182 g cm -3. The relevant parameters for the -100*C structure are a = 9.557(4), b ---I0.980(2), and c = 9.641(2) ,~,/~ = 106.34(3)~ V = 970.76 ,~3 and d(calc; z = 4) = 1.199 gcm -3. Final values were R(F) = 0.042, Rw = 0.035, using unit weights, and its nonhydrogen atoms were used to phase the low-temperature data, whose final discrepancy indices were R(F) = 0.051, Rw = 0.061. The phenyl substituent is almost exactly in the bisecting conformation with respect to the C--C--C angle at the point of attachment to cyclopropane and conjugative effects are clearly evident in the lengths of the cyclopropane ring [1.494(3), 1.498(3), and 1.474(4) A, the later being the distal bond]. If one omits the terminal methylene fragments at C 10 and C 11, the atoms comprising the acetanilide fragment and the substituted carbon of the cyclopropane ring lie in a nearly perfect plane. Molecular mechanics as well as semiempirical (AM 1) calculations were carried out in order to determine the structure of the energy-minimized configurations in the two computational environments. The molecular conformations thus obtained are close to that experimentally observed from the X-ray diffraction experiment. In both theoretical models, the lowest energy conformation is that in which the plane of the phenyl ring bisects the cyclopropane C--C--C angle as was experimentally observed. Finally, the shape of the conformational barrier as a function of the orientation of the plane of the phenyl ring was computed, giving a maximum barrier to rotation of 2.2 kcal/mol. Similar calculations were carried out for two other aryl cyclopropanes, whose rings (naphthalene and anthracene) cannot adopt the bisecting position. Comparisons of experimental geometrical parameters as well as of the barriers to rotation are presented.

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Section: ~Troductionmentioning

confidence: 86%

Section: ~Troductionmentioning

confidence: 94%

Crystal structures of phenyl-substituted cyclopropanes. IV. the crystal structure (at 21‡C and −100‡C) and the phenyl ring conformation in 4-cyclopropylacetanilide

et al. 1997

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Structural Chemistry of Cyclopropane Derivatives

Rozsondai

2009

Patai's Chemistry of Functional Groups

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Introduction Cyclopropane Substituted Cyclopropanes Cyclopropylidenes Cyclopropenes Cyclopropenylidenes and Related Systems Cyclopropane Rings in Polycyclic Systems Acknowledgements

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ChemInform Abstract: Conglomerate Crystallization in Organic Compounds. Part 2. The Conformation, Configuration, and Spontaneous Resolution of 1‐Phenyl‐2‐cyano‐cyclopropane.

1991

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Conglomerate crystallization in organic compounds II. The conformation, configuration, and spontaneous resolution of 1-phenyl-2-cyano-cyclopropane

Cited by 5 publications

References 14 publications

Crystal structures of phenyl-substituted cyclopropanes. IV. the crystal structure (at 21‡C and −100‡C) and the phenyl ring conformation in 4-cyclopropylacetanilide

Crystal structures of phenyl-substituted cyclopropanes. IV. the crystal structure (at 21‡C and −100‡C) and the phenyl ring conformation in 4-cyclopropylacetanilide

Structural Chemistry of Cyclopropane Derivatives

ChemInform Abstract: Conglomerate Crystallization in Organic Compounds. Part 2. The Conformation, Configuration, and Spontaneous Resolution of 1‐Phenyl‐2‐cyano‐cyclopropane.

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