1700-10-3Relevant articles and documents
Enantiodifferentiation in the Photoisomerization of (Z,Z)-1,3-Cyclooctadiene in the Cavity of γ-Cyclodextrin-Curcubit[6]uril-Wheeled [4]Rotaxanes with an Encapsulated Photosensitizer
Yan, Zhiqiang,Huang, Qinfei,Liang, Wenting,Yu, Xingke,Zhou, Dayang,Wu, Wanhua,Chruma, Jason J.,Yang, Cheng
, p. 898 - 901 (2017)
A biphenyl photosensitizer axle was implanted into the cavities of native and capped γ-cyclodextrins through rotaxanation using a cucubit[6]uril-templated azide-alkyne 1,3-dipolar cycloaddition, resulting in the construction of highly defined chiral binding/sensitizing sites. The orientation and interaction of the axle and capping moieties at the ground and excited states were interrogated by NMR, UV-vis, circular dichroism, and fluorescence spectroscopic studies. In situ photoisomerization of (Z,Z)-1,3-cyclooctadiene sensitized in the cavity of these [4]rotaxanes afforded (Z,E)-1,3-cyclooctadiene in up to 15.3% ee, which represents the highest level of enantiodifferentiation obtained to date for this supramolecular photochirogenesis.
Optically active (E,Z)-1,3-cyclooctadiene: First enantioselective synthesis through asymmetric photosensitization and chiroptical property
Inoue, Yoshihisa,Tsuneishi, Hiroshi,Hakushi, Tadao,Tai, Akira
, p. 472 - 478 (1997)
Enantiodifferentiating photoisomerizations of (Z,Z)-1,3-cyclooctadiene (1ZZ) to the chiral E,Z-isomer 1EZ were performed at varying temperatures in the presence of some benzenepoly-, naphthalene(di)-, and anthracenecarboxylates. Of these chiral sensitizers, (-)-menthyl benzenehexacarboxylate afforded the highest enantiomeric excesses (ee's) up to 10% and 18% in pentane at 25 and -40°C, respectively. In contrast, the use of polar solvents greatly diminished the product's ee, suggesting intervention of a radical ionic rather than exciplex intermediate in these solvents. Optically pure 1EZ is shown to possess anomalously high specific rotation and circular dichroism as a simple diene chromophore: [α]25(D) 1380°(CH2Cl2), Δε 12.8 M-1 cm-1 (λ(ext) 228 nm, cyclohexane). The chiroptical properties observed not only correct the previous data but also present the conclusive evidence for the recent theoretical predictions.
Enantiodifferentiating photoisomerization of (Z, Z)-1,3-cyclooctadiene included and sensitized by naphthoyl-curdlan
Fukuhara, Gaku,Imai, Mami,Yang, Cheng,Mori, Tadashi,Inoue, Yoshihisa
supporting information; experimental part, p. 1856 - 1859 (2011/06/22)
6-O-(2-Naphthoyl)curdlan was newly synthesized as a sensitizing polysaccharide host to examine the chiroptical properties, supramolecular complexation, and photochirogenic behavior with (Z,Z)-1,3-cyclooctadiene (1ZZ). The enantiodifferentiating photoisomerization of 1ZZ included and sensitized by this polysaccharide host gave a highly strained chiral (E,Z)-isomer in up to 8.7% enantiomeric excess (ee) in solution and 11.7% ee in the solid state, which are the highest values ever reported for a supramolecular photochirogenesis of 1EZ.
Investigation of Rearrangement Reactions of Cyclic Allyl and Pentadienyl Anions
Sustmann, Reiner,Dern, Heinz-Juergen
, p. 2958 - 2971 (2007/10/02)
Bicyclohexenyl anion (1) and bicycloheptenyl anion (2) rearrange in THF to monocyclic pentadienyl anions, whereas bicyclooctenyl anion 3 is stable under the reaction conditions. 3 in contrary is formed by the known electrocyclic ring closure of cyclooctadienyl anion 7.Rearrangements of cyclopentenyl anion and pentadienyl anion are not detected.Cyclic allyl anions are alkylated by ethene, formed by cleavage of THF with base or independently added. 6,6-Dimethylcyclohexadienyl anion undergoes slow fragmentation to toluene at room temperature.
CYCLIC α,β-EPOXYSILANES ACID-CATALYSED REACTIONS OF 1-TRIMETHYLSILYLCYCLOOCTENE OXIDE
Nagendrappa, Gopalpur
, p. 2429 - 2434 (2007/10/02)
The acid-catalysed reactions of medium ring α,β-epoxysilane 1 are described.The epoxide 1 gives exclusively the bicyclic alcohol 2 with boron trifluoride etherate.With aqueous sulphuric acid the products are due to both transannular ring closure, 2, and transannular hydride migration, 3 and 4. trans-Cyclooctene derivatives 3 and 4 are formed by the trans-elimination of trimethylsilanol from the likely intermediate β-hydroxysilanes 10 and 11.The results with methanolic sulphuric acid are similar.It is also noticed that the hydride migration is facilitated by the nucleophilic strength of the medium.