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Search for "helical chirality" in Full Text gives 11 result(s) in Beilstein Journal of Organic Chemistry.
Construction of hexabenzocoronene-based chiral nanographenes
Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54
- [20][21][22][23][24]. Currently, there is a great interest in the introduction of chirality into large conjugated polyaromatics to obtain chiral NGs with chiroptical properties. Among these chiral NGs, helicenes represent the dominant chiral compounds by virtue of their inherent helical chirality [25
Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures
Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81
- ; selenophene; thiophene; Introduction Given their esthetically pleasing helical structures, inherent helical chirality, and extended π-conjugation, helicenes have attracted extensive research attention. Helicenes are generally divided into carbohelicenes and heterohelicenes. The rapid development of
Copper catalysis with redox-active ligands
Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77
- iminosemiquinone redox-active ligand which was oxidized to iminobenzoquinone. The Canary group [30] reported a redox-reconfigurable copper catalyst that exhibits reversal of its helical chirality through redox stimuli (Scheme 8). Combining ʟ-methionine and catalytic urea groups with two different copper salts as
- precursors affords both enantiomers Δ-10 (from CuClO4) and Λ-10 from (Cu(CH3CN)4PF6). UV–vis and circular dichroism spectroscopic studies evidence that the helical chirality exhibited by these two catalysts could be reversed by redox stimuli. These complexes could perform enantioselective Michael addition
- trifluoromethylation of heteroaromatics with redox-active iminosemiquinone ligands. Reversal of helical chirality upon redox stimuli and enantioselective Michael addition with a redox-reconfigurable copper catalyst. Interaction of guanidine-copper catalyst with oxygen and representative coupling products. a4 mol
Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes
Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154
- engages in double hydrogen bonding to form an 11-membered ring, resulting in the chiral helicity. The helical chirality induced in iodine(III) derivatives of 23 bearing the bislactamide motif was described for 27 with an efficient differentiation of the enantiotopic faces of the styrene substrate. This
Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial
Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5
- [5]. As nucleic acids are characterized by a dominant helical chirality and exhibit a rather small set of secondary structures, each characterized by a different polarization spectroscopy signature, they are convenient targets to monitor structural changes induced by outer stimuli. Linear dichroism
- polynucleotides, particularly in the double-stranded helix of DNA or RNA, introduces helical chirality, whereby the helical axis is almost perpendicular to the aromatic base-pair plane. In this situation, the ECD changes dramatically as a consequence of the so-called coupled oscillator or exciton coupling
- range indicates a disruption of helical chirality by intercalation or severe kinking of the helix by sterically demanding groove binders. At variance, if the ECD spectrum of the DNA and RNA does not change significantly, the biopolymer helical structure is preserved, suggesting a ligand groove binding
Selected synthetic strategies to cyclophanes
Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142
- conformation that imparts helical chirality. Double helically twisted chiral cyclophanes are important macrocycles due to their potential applications in optics and electronics. Kawase and co-workers [121] have reported the synthesis of 8,14,30,36-tetramethoxy[2.0.2.0](1,6)naphthalenophane-1,19-diyne (102
Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones
Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124
- by the combination of chirality with the TTF motif, a certain number of families of precursors have been reported. They possess various types of chirality, i.e., stereogenic centers, axial, planar, helical chirality, and supramolecular chirality [17][18][19][20][21]. Since methylated BEDT-TTF
A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)
Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2
- polycyclic aromatic compounds, have been fascinating organic chemists over the last century since the first synthesis of azahelicenes was reported by Meisenheimer in 1903 [1], not only because of their aesthetically attractive structures, but also because of their unique properties arising from the helical
- chirality [2][3][4][5][6][7][8][9][10][11]. In fact, helicenes have been finding more and more potential applications such as optoelectronic materials, asymmetric catalysts, and chemosensors [9]. Therefore, the development of synthetic methods for the preparation of helicenes which are difficult to access
Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives
Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225
- ), whereas the isoelliptic points supported the formation of only one type of the compound/DNA or RNA complex. The intensity decrease of ds-DNA/RNA CD bands is usually associated with the partial disruption of the polynucleotide helical chirality caused by the binding of a small molecule. The reference
Design and synthesis of quasi-diastereomeric molecules with unchanging central, regenerating axial and switchable helical chirality via cleavage and formation of Ni(II)–O and Ni(II)–N coordination bonds
Beilstein J. Org. Chem. 2012, 8, 1920–1928, doi:10.3762/bjoc.8.223
- *) and (Ra*,Ph*,Rc*) occurs by intramolecular trans-coordination of Ni–NH and Ni–O bonds providing a basis for a chiral switch model. Keywords: axial chirality; central chirality; chiral switches; coordination bonds; functional materials; helical chirality; modular structural design; molecular devices
- molecules with unchanging central, regenerating axial, and switchable helical chirality, through cleavage/formation of Ni(II)–O and Ni(II)–N coordination bonds. Recently, we introduced a new approach to the design of organic molecules with switchable chirality by simple cleavage and formation of metal
- chelating ring resulting in a screw sense of helical chirality. The transcoordination motion in these complexes is expected to be controlled in a way that noncoordinated sites, i.e., E in 5 and A in 6, will move up and down, respectively, resulting in the interconversion of complexes 5 and 6. This assumed
Organocatalytic C–H activation reactions
Beilstein J. Org. Chem. 2012, 8, 1374–1384, doi:10.3762/bjoc.8.159
- of the (R)-isomer. Even when achiral catalyst Yb(OTf)3 was used for the reaction with (S)-18, product 19 was obtained with 85% ee with the (S)-enantiomer as the major product. This clearly demonstrates that the chiral information in 18 did not disappear during the reaction and was retained as helical
- chirality in cationic intermediate C (Scheme 13). Nucleophilic attack then occurred from the same side of the transferred hydrogen to provide (S)-19. The authors concluded that selective activation of one of the enantiotopic hydrogen atoms by chiral phosphoric acid is the main reason for obtaining
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