Optical Activity in Skewed Dienes

Moscowitz, Albert; Charney, Elliot; Weiß, Ulrich; Ziffer, Herman

doi:10.1021/ja01483a040

Cited by 132 publications

(48 citation statements)

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“…26 For the twisted cisoid 1,3-butadiene moiety itself, in which the 1 and 4 positions are not linked by two sp 3 hybridized carbons, as they are in 1,3-cyclohexadienes, these calculations agree with the original diene helicity rule 28 by predicting a positive, though not necessarily very strong, 27 CE for P diene chirality. As seen here, structural and substituent effects clearly determine the strength of the lowest-energy CEs of chiral nonhomoannular cisoid conjugated dienes.…”

Section: Resultssupporting

confidence: 55%

Diene chirality and cotton effects of nonhomoannular cisoid conjugated dienes: Circular dichroism and crystal structure of a steroidal 19‐nor‐1(10),9(11)‐diene derived from westphalen's diol diacetate

Burgstahler¹,

Jahansouz²,

Véliz³

et al. 2002

Chirality

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Nonhomoannular cisoid conjugated dienes exhibit negative lowest energy pi-->pi* Cotton effects when they have P diene chirality and positive CEs when they have M diene chirality. We investigated this relationship further with a variety of such dienes by MM2 conformational energy-minimization calculations and by an X-ray crystal structure of a steroidal 19 nor 1(10),9(11) diene. CEs are stronger when each double bond of the diene is endocyclic in a different ring and weaker when only one of the double bonds is endocyclic or when neither double bond is endocyclic. They are also stronger when axial allylic and homoallylic substituents with CH/pi interactions are present that exert consignate chirality contributions.

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Section: Resultssupporting

confidence: 55%

Diene chirality and cotton effects of nonhomoannular cisoid conjugated dienes: Circular dichroism and crystal structure of a steroidal 19‐nor‐1(10),9(11)‐diene derived from westphalen's diol diacetate

Burgstahler¹,

Jahansouz²,

Véliz³

et al. 2002

Chirality

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“…They might be employed to test the models and rules in circular dichroi'sm [5], e.g. : allylic chirality method [6], s-cis-diene helicity rule [7], couple oscillatorexciton chirality theory [8], amplified sector rule [9], general sector rule [ lo], electric dipole @)-magnetic dipole (m) coupling mechanism [I 11, through-bond mechanism [12] and the Generalized Octant Rule [13].…”

mentioning

confidence: 99%

Optical activity in remotely perturbed exocyclic s‐cis‐butadienes. Preparation and circular dichroism of enantiomerically pure 5,6‐dimethylidene‐2‐norbornyl derivatives

Sonney¹,

Vogel²

1980

Helvetica Chimica Acta

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SummaryOptically pure 5,6-dimethylidene-exo-2-norbornanol ( The solution CD. spectra of these remotely perturbed exocyclic s-cis-butadienes are reported and discussed briefly. Unexpectedly, the p, y-unsaturated ketone (+ )-7, for which transannular interaction between the ketone and diene functions was revealed by its UV. absorption spectrum, showed (in isooctane) two weak Cotton effects of opposite sign between 265 and 340 nm.Introduction. -Optically pure 5,6-dimethylidene-2-norbornyl derivatives 1-7 are interesting systems for at least three reasons: 1) The Diels-Alder additions (e.g of 4 and of 7) to strong dienophiles are regio-and stereoselective [3]; thus, if enantiomerically pure, these dienes might become useful synthons for the preparation of complex, polycyclic molecules; 2) the exo-and endo-5,6-dimethylidene-2-norbornyl brosylates (3 and 6 ) are convenient starting materials for the study of the n-participation by the 'back' of an exocyclic s-cis-butadiene group in the S,1-solvolyses of the esters [4]; 3) The dienes 1-6 as well as the keto-diene 7 are remotely perturbed exocyclic dienes (no direct substitution) maintained in a

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“…290 nm region. In recent theoretical studies on the p,y-unsaturated ketones, [13][14][15] this interaction has been explained by elec- trostatic coupling or the dipole-dipole coupling between the n--->n* transition of the carbonyl and the n---+n* transition of the (3,ydouble bond. Judging from the clear couplet CD curves of the Type A-I lactones shown in Figs.…”

Section: Methodsmentioning

confidence: 99%

Circular Dichroic Studies on Marmelo Lactones and the Related γ-Lactones with Unsaturation at the C-5 Position

Nishida

Ohrui

Meguro

et al. 1986

Agricultural and Biological Chemistry

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Optical Activity in Skewed Dienes

Cited by 132 publications

References 0 publications

Diene chirality and cotton effects of nonhomoannular cisoid conjugated dienes: Circular dichroism and crystal structure of a steroidal 19‐nor‐1(10),9(11)‐diene derived from westphalen's diol diacetate

Diene chirality and cotton effects of nonhomoannular cisoid conjugated dienes: Circular dichroism and crystal structure of a steroidal 19‐nor‐1(10),9(11)‐diene derived from westphalen's diol diacetate

Optical activity in remotely perturbed exocyclic s‐cis‐butadienes. Preparation and circular dichroism of enantiomerically pure 5,6‐dimethylidene‐2‐norbornyl derivatives

Circular Dichroic Studies on Marmelo Lactones and the Related γ-Lactones with Unsaturation at the C-5 Position

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