931-89-5Relevant academic research and scientific papers
Efficient approach to medium-sized cyclic molecules containing (E)-Alkene via z to e photochemical isomerization in the presence of AgNO3-impregnated silica gel
Machida, Kouhei,Yoshida, Yuki,Igawa, Kazunobu,Tomooka, Katsuhiko
supporting information, p. 186 - 188 (2018/02/06)
Efficient synthesis of medium-sized cyclic molecules containing an (E)-alkene was performed via the highly (E)selective photochemical isomerization of the (Z)-isomer, facilitated by AgNO3-impregnated silica gel.
Photochirogenic nanosponges: phase-controlled enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by pyromellitate-crosslinked linear maltodextrin
Liang, Wenting,Zhao, Meiling,Wei, Xueqin,Yan, Zhiqiang,Wu, Wanhua,Caldera, Fabrizio,Trotta, Francesco,Inoue, Yoshihisa,Su, Dan,Zhong, Zhihui,Yang, Cheng
, p. 17184 - 17192 (2017/03/30)
Linear maltodextrin (LM) was cross-linked by pyromellitic dianhydride to afford LM polymers of different cross-linking degrees. When soaked in water, these cross-linked LM polymers (nanosponges (NSs)), evolved into several phases from sol to suspension, then to flowing gel, and finally to rigid gel with an increase in their content. Enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to chiral (E)-isomer (1E), which was employed as a benchmark reaction to quantitatively assess the environmental-to-molecular chirality transfer process, was performed in aqueous media containing these pyromellitate-crosslinked LM-NSs in different phases. The enantiomeric excess (ee) of 1E obtained was relatively insensitive to the phases at least up to the flowing gel phase, but became highly sensitive in the rigid gel phase, exhibiting an abrupt drop in the early rigid gel phase followed by a rapid recovery in the late rigid gel phase. A comparison with the phase-dependent ee profiles previously reported for similar pyromellitate-crosslinked cyclodextrin (CD)- and cyclic nigerosylnigerose (CNN)-NSs revealed that the chiral void space created around the pyromellitate linker in NS is responsible for the dramatic changes in ee in the rigid gel phase, whereas the inherent host cavity in CD/CNN plays only limited roles in the supramolecular photochirogenesis mediated by the sensitizer-crosslinked NSs. The latter insight allows us to further expand the applicable range of the present concept and methodology by employing a much wider variety of oligosaccharides as well as substrates and sensitizing cross-linkers.
Efficient low-cost preparation of trans-cyclooctenes using a simplified flow setup for photoisomerization
Svatunek, Dennis,Denk, Christoph,Rosecker, Veronika,Sohr, Barbara,Hametner, Christian,Allmaier, Günter,Fr?hlich, Johannes,Mikula, Hannes
, p. 579 - 585 (2016/03/19)
Bioorthogonal ligations have emerged as highly versatile chemical tools for biomedical research. The exceptionally fast reaction between 1,2,4,5-tetrazines and trans-cyclooctenes (TCOs), also known as tetrazine ligation, is frequently used in this regard. Growing numbers of applications for the tetrazine ligation led to an increased demand for TCO compounds, whose commercial availability is still very limited. Reported photochemical procedures for the preparation of TCOs using flow chemistry are straightforward and high yielding but require expensive equipment. Within this contribution, we present the construction and characterization of a low-cost flow photoreactor assembled from readily accessible components. Syntheses of all commonly used trans-cyclooctene derivatives were successfully carried out using the described system. We are convinced that the presented system for photoisomerization will promote access to bioorthogonally reactive TCO derivatives.
Solvent- and phase-controlled photochirogenesis. Enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by cyclic nigerosylnigerose-based nanosponges crosslinked by pyromellitate
Wei, Xueqin,Liang, Wenting,Wu, Wanhua,Yang, Cheng,Trotta, Francesco,Caldera, Fabrizio,Mele, Andrea,Nishimoto, Tomoyuki,Inoue, Yoshihisa
, p. 2905 - 2912 (2015/04/27)
Cyclic nigerosylnigerose (CNN), a saucer-shaped cyclic tetrasaccharide with a shallow concave surface, was reacted with pyromellitic dianhydride in 1 : 2 and 1 : 4 ratios to give two CNN-based polymers of different degrees of crosslinking, both of which swelled upon soaking in water, acting as a 'nanosponge' (NS). These NSs evolved several phases from isotropic solution to flowing and rigid gels via suspension by gradually increasing the concentration in water. The CNN-NSs thus prepared effectively mediated the enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to chiral (E)-isomer (1E). The enantiomeric excess (ee) of 1E obtained was a critical function of the solvent composition and the phase evolved at different CNN-NS concentrations in water. In isotropic solution, the enantioselectivity was generally low (-4% to +6% ee) but the chiral sense of 1E was inverted by increasing the methanol content. Interestingly, the product's ee was controlled more dramatically by the phase evolved, as was the case with the cyclodextrin-based nanosponge (CD-NS) reported previously. Thus, the ee of 1E was low in solution and suspension, but suddenly leaped at the phase border of flowing gel and rigid gel to give the highest ee of 22-24%, which are much higher than those obtained with CD-NSs (6-12% ee), revealing the positive roles of the chiral void space formed upon gelation of the crosslinked saccharide polymer.
Phase-controlled supramolecular photochirogenesis in cyclodextrin nanosponges
Liang, Wenting,Yang, Cheng,Zhou, Dayang,Haneoka, Hitoshi,Nishijima, Masaki,Fukuhara, Gaku,Mori, Tadashi,Castiglione, Franca,Mele, Andrea,Caldera, Fabrizio,Trotta, Francesco,Inoue, Yoshihisa
supporting information, p. 3510 - 3512 (2013/05/09)
Pyromellitate-bridged cyclodextrin nanosponges (CDNSs) evolved from sol into gel state upon gradual increase of the concentration from 0.2 to 2000 mg mL-1 in water. The enantiodifferentiating geometrical photoisomerizations of (Z)-cyclooctene and (Z,Z)-1,3-cyclooctadiene sensitized by CDNS at various concentrations were critically affected by the phase transition of CDNS to afford the corresponding (E)- and (E,Z)-isomers in the highest enantiomeric excesses in the gel state.
Supramolecular photochirogenesis with novel cyclic tetrasaccharide: Enantiodifferentiating photoisomerization of (Z)-cyclooctene with cyclic nigerosylnigerose-based sensitizers
Yang, Cheng,Liang, Wenting,Nishijima, Masaki,Fukuhara, Gaku,Mori, Tadashi,Hiramatsu, Hiroyuki,Dan-Oh, Yasufumi,Tsujimoto, Kazuo,Inoue, Yoshihisa
, p. 921 - 927 (2013/01/15)
Isophthalic and terephthalic acid monoesters of cyclic nigerosyl-(1→6) -nigerose (CNN), a cyclic tetrasaccharide composed of four d-glucopyranosyl residues connected by alternating α-1,3- and α-1,6-linkages, were synthesized as novel chiral supramolecular sensitizers for enantiodifferentiating photoisomerization of (Z)-cyclooctene () to planar chiral (E)-isomer (1E). Despite the saucer-shaped shallow cavity of CNN that does not immediately guarantee strong ground-state interactions with, the sensitizer-appended CNNs afforded optically active 1E in such enantiomeric excesses that are much improved than those obtained with an α-cyclodextrin analog and comparable with those obtained with a β-cyclodextrin analog. Interestingly, the enantiomeric excess values obtained were a critical function of temperature and solvent to show an inversion of the product chirality by changing the environmental variants. Nevertheless, all of the differential activation parameters calculated from the temperature-dependent enantiomeric excesses gave an excellent compensatory enthalpy-entropy relationship, indicating an operation of a single enantiodifferentiating mechanism in the present chiral photosensitization with modified CNNs. Chirality 24:921-927, 2012. 2012 Wiley Periodicals, Inc. Copyright
Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by benzoate modified β-cyclodextrin derivatives: Switching of product chirality by solvent
Li, Guangxun,Wang, Zhizhong,Lu, Runhua,Tang, Zhuo
experimental part, p. 3097 - 3101 (2011/06/26)
Solvent effect upon asymmetric photosensitization has been investigated in the enantiodifferentiating photoisomerization of cyclooctene(1Z), sensitized by benzoate modified β-cyclodextrin derivatives bearing nitrogen, oxygen or sulfur substituents. The enantiomeric excess (ee) and E/Z ratio of reaction products were susceptible to the concentration of methanol in the aqueous solution, which could switch to the chirality of product unprecedentedly. Further investigation indicated that the conformation of the modified CDs in aqueous methanol solutions with 1Z were highly sensitive to both the substituent(s) on benzoate moiety of the modified CDs and the concentration of methanol. Solvent content represents a new versatile tool to efficiently manipulate the asymmetric photochemical reactions, in which the chirality of products can be switched by simply changing the methanol content of reaction solvent rather than synthesizing the antipodal sensitizers.
Planar-to-planar chirality transfer in the excited state. Enantiodifferentiating photoisomerization of cyclooctenes sensitized by planar-chiral paracyclophane
Maeda, Ryo,Wada, Takehiko,Mori, Tadashi,Kono, Shigeyuki,Kanomata, Nobuhiro,Inoue, Yoshihisa
supporting information; experimental part, p. 10379 - 10381 (2011/09/13)
Photochemical planar-to-planar chirality transfer was effected by using (R)-[10]paracyclophane-12-carboxylates as a planar-chiral sensitizer and (Z)-cyclooctene and (Z,Z)-1,5-cyclooctadiene as prochiral substrates to give a planar-chiral (E)- and (E,Z)-isomer in up to 44% and 87% enantiomeric excess, respectively, the latter of which being the highest ever reported for a sensitized photochirogenic reaction.
A photochemical synthesis of functionalized trans-cyclooctenes driven by metal complexation
Royzen, Maksim,Yap, Glenn P. A.,Fox, Joseph M.
, p. 3760 - 3761 (2008/12/20)
Described is a scalable procedure for driving photochemical sytheses of trans-cyclooctene derivatives through metal complexation. During photoirradiation, reaction mixtures are continuously pumped through a column of a AgNO3-impregnated silica gel. The trans-cyclooctene derivative is selectively retained by the AgNO3-impregnated silica, but the cis-isomer elutes from the column back to the reaction flask, where it is photoisomerized and recirculated through the column. The method provides access to a range of usefully functionalized derivatives of trans-cyclooctene, including a derivative of 5-aza-trans-cyclooctene that underwent transannular cyclization upon treatment with bromine. The alkene stereochemistry is transferred with high fidelity to the hexahydropyrrolizine framework in the transannular cyclization. Copyright
Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by aroyl-β-cyclodextrins: A critical enantioselectivity control by substituents
Lu, Runhua,Yang, Cheng,Cao, Yujuan,Tong, Linhui,Jiao, Wei,Wada, Takehiko,Wang, Zhizhong,Mori, Tadashi,Inoue, Yoshihisa
, p. 7695 - 7701 (2008/12/23)
(Chemical Equation Presented) A series of 6-O-benzoyl-β-cyclodextrins (CDs) with methyl, methoxy, methoxycarbonyl, and bromo substituent(s) at the ortho-, meta-, and/or para-position(s) were synthesized as chiral sensitizing hosts for the use in supramole
