Homoconjugation and transannular orbital interactions detected by photoelectron and carbon-13 NMR spectroscopy. Bicyclo[3.3.1]nona-3,7-diene-2,6-dione and bicyclo[3.3.1]nonane-2,6-dione

Doerner, Thomas; Gleiter, Rolf; Robbins, Timothy A.; Chayangkoon, Paochai; Lightner, David A.

doi:10.1021/ja00035a011

Cited by 29 publications

(18 citation statements)

References 3 publications

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“…The transannular interaction of enone chromophores in this compound has been demonstrated earlier by photoelectron spectroscopy [18] in comparison to enone 7 as well as by their chemical reactivity leading to intramolecular ring closure. [23] In addition, the molecular structure of 9 has a slightly nonplanar arrangement of chromophores (calculated torsional angle 2º), and this helicity contributes to the intensity of the CD absorption.…”

Section: Discussionsupporting

confidence: 58%

“…The residue was subjected to a second fermentation for an additional 6 d, the products were then separated as above and purified by flash chromatography (CHCl 3 ) to yield 6 g (59 %) of (+)-(1S,5S)-diketone 1, ee Ͼ99 % (GC). The Lightner procedure [18] of monothioketalization was followed with 0.30 g of diketone 1 to afford 0.38 g (83 %) of 5.…”

Section: Methodsmentioning

confidence: 99%

“…By analogy, enone 7 was synthesized in 95 % yield from monoketone 6, which was obtained by protection of one carbonyl group in diketone 1 with a slight modification of the reported procedure (Scheme 2). [18] Scheme 2. (a) PhIO 2 , PhSeSePh, TsOH (cat.…”

Section: Synthesis Of Bicyclo[331]nonenonesmentioning

confidence: 99%

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Enantiospecific Synthesis and Chiroptical Properties of Bicyclic Enones

et al. 2007

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The enantiospecific synthesis of several bicyclic enones starting from enantiomerically pure (+)‐(1S,5S)‐bicyclo[3.3.1]nonane‐2,6‐dione (1) was accomplished. The target enones 7–9 were obtained in high yield and purity by using a catalytic amount of benzeneselenic anhydride. (+)‐(1S,5R)‐bicyclo[3.3.1]nonane‐2,3,6‐trione was obtained from diketone 1 by α‐hydroxylation involving the use of iodine under basic conditions. The reaction included a ring closure/reopening sequence via oxatricyclo[4.3.1.03,8]decane‐10‐one. It was shown that the latter triketone exists in enone/enol form. Chiroptical properties of the enantiomerically pure compounds were studied, and the sign of the Cotton effect was related to the absolute configuration of the enones. The positive Cotton effect in the bisignate CD curve is accounted for by the nonplanarity of the chromophore in enones (1S,5R)‐4 and (1S,5S)‐8. The circular dichroism spectra provided evidence for interchromophoric interaction in dichromophoric bis(enone) 9. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Discussionsupporting

confidence: 58%

Section: Methodsmentioning

confidence: 99%

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Enantiospecific Synthesis and Chiroptical Properties of Bicyclic Enones

et al. 2007

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“…Bicyclic frameworks were shown to be particularly well suited for the studies of electron delocalization through homoconjugation in terms of direct (“through-bond”) and indirect (“through-space”) interactions from localized sets of orbitals or chromophores. Such interaction of π–electron systems in norbornadienes [27], norbornenones [28], barrelenes [29], bicyclo[3.3.1]nona-dienones [30] and related frameworks [31] was evidenced by photoelectron, NMR and CD spectroscopy. In the case of 3 and 4 , two localized (isolated) chromophores are predisposed to transannular through-space interaction due to a favourable conformation of bicyclic skeleton and a rather small interchromophoric distance (ca.…”

Section: Resultsmentioning

confidence: 99%

Homoconjugation vs. Exciton Coupling in Chiral α,β-Unsaturated Bicyclo[3.3.1]nonane Dinitrile and Carboxylic Acids

2014

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Abstract:The chiroptical properties of enantiomerically pure bicyclo[3.3.1]nona-2,6-diene-2,6-dicarbonitrile and related acids were studied by circular dichroism spectroscopy and theoretical computations. A consideration of the molecular structure of the synthesized difunctional compounds revealed that chromophores are predisposed to transannular through-space interaction due to a favourable conformation of the bicyclic skeleton and a rather small interchromophoric distance. Evidence for non-exciton-type coupling between the two acrylonitrile and acrylate moieties in 3 and 4, respectively, was obtained by chiroptical spectroscopy and DFT calculations.

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“…Visualization was accomplished by UV light or with p-anisaldehyde and basic KMnO 4 solutions. 8-Aminoquinoline-7-carbaldehyde [26] [29,30] were obtained according to the reported procedures. cis-Bicyclo [3.3.0]octane-3,7-dione is commercially available.…”

Section: Methodsmentioning

confidence: 99%