Benzanelliertes Doppel‐[7]Carbohelicen: Synthese, Struktur und physikochemische Eigenschaften

Abstract

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π‐Extended Diaza[7]helicenes by Hybridization of Naphthalene Diimides and Hexa‐peri‐hexabenzocoronenes

“…The second buildingb lock NDI-compound 5 was prepared via condensation of naphthalene monoimide (8)w ith diamino-bromobenzene (11)( Scheme 3). During this reaction, two constitutional isomers are formed, 5 as well as 5-bromo-1,2-naphthaleneimidebenzimidazole (12). The two compounds can easily be separated by column chromatography,i solatingt he first yellow fraction in 42 %y ield, and the second orange fractioni n3 6% yield.…”

“…All chromatograms were processed with Shimadzu LabSolution(c) software and exported as ASCII files. 4/5-Bromo-1,2-naphthaleneimidebenzimidazole (5) and (12):A dry flask was charged with NMI 8 (100 mg, 0.237 mmol, 1.1 equiv), 4-bromo-1,2-diaminbenzene 11 (40.0 mg, 0.216 mmol, 1equiv) and imidazole (800 mg) and the mixture was stirred under nitrogen at 160 8Cf or 3h.T he reaction mixture was cooled to rt, diluted in DCM and washed with H 2 O. The combined organic layers were concentrated under reduced pressure and the crude was purified by silica gel column chromatography (SiO 2 ,D CM/hexanes 1:1) to provide the two separated isomers 5 and 12 in ap ure form.…”

Synthesis of Single and Double Dibenzohelicenes by Rhodium‐Catalyzed Intramolecular [2+2+2] and [2+1+2+1] Cycloaddition

“…[18] It is noteworthy that 4 showedasignificantly high quantum yield (0.75), whichi sm arkedlyh igher than that of the previously reportedd oubled ibenzo [7]helicene (0.34). [8] This is because the luminophore in 4 is the peropyrene moiety,w hich is known as as trongly luminescentm olecule (0.90). [19] Furthermore, the peropyrene luminophore of 4 is less twisted than that of the double dibenzo [7]helicene, whichw ould accountf or the observed markedlyh igherq uantum yield of 4 compared to the double dibenzo [7]helicene.…”

“…[4i, 7] Starý,S tarµ,a nd co-workers recentlyr eported the enantioselective synthesis of dibenzo [7]helicenes with up to 86 % ee by nickel(0)-catalyzed intramolecular [2+ +2+ +2] cycloadditiono f2 -phenylnaphthalene-linked triynes,w hereast heir structures and photophysical/chiroptical properties were not examined, and highly enantioselective transformation was limited to the case of at erminal triyne for dibenzo [7]helicenes. [8] On the other hand, we reported the enantioselective synthesis of [7]helicene-like molecules with up to 85 % ee by cationic rhodium(I)/bis-phosphine complex-catalyzedi ntramolecular [2+ +2+ +2] cycloaddition of 2-naphthol-linked triynes (Scheme 1, top). [8] On the other hand, we reported the enantioselective synthesis of [7]helicene-like molecules with up to 85 % ee by cationic rhodium(I)/bis-phosphine complex-catalyzedi ntramolecular [2+ +2+ +2] cycloaddition of 2-naphthol-linked triynes (Scheme 1, top).…”

“…[4a, h] As an example of ad ibenzo-fused double helicene, Narita, Müllen, and co-workers reported the design ands ynthesis of ad ouble dibenzo [7]helicene by the Scholl reaction, whichg ave am ixture of chiral and meso isomers. [8] On the other hand, we reported the enantioselective synthesis of [7]helicene-like molecules with up to 85 % ee by cationic rhodium(I)/bis-phosphine complex-catalyzedi ntramolecular [2+ +2+ +2] cycloaddition of 2-naphthol-linked triynes (Scheme 1, top). [9] Interestingly,n ot only the [2+ +2+ +2] cycloaddition but also the formal [2+ +1+ +2+ +1] cycloaddition involving the CÀCt riple-bondc leavage [10] proceeded to give achiral ladder-type compounds.…”