Enantioselective synthesis of molecules with multiple stereogenic elements

Chemical Society Reviews, Год журнала: 2024, Номер 53(22), С. 11165 - 11206

Опубликована: Янв. 1, 2024

This review explores the fascinating world of molecules featuring multiple stereogenic elements, unraveling different strategies designed over years for their enantioselective synthesis.

Язык: Английский

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Impact of helical elongation of symmetric oxa[n]helicenes on their structural, photophysical, and chiroptical characteristics

Chirality, Год журнала: 2024, Номер 36(5)

Опубликована: Май 1, 2024

Abstract The adjustment of the main helical scaffold in helicenes is a fundamental strategy for modulating their optical features, thereby enhancing potential diverse applications. This work explores influence elongation (n = 5–9) on structural, photophysical, and chiroptical features symmetric oxa[ n ]helicenes. Crystal structure analyses revealed structural variations with extension, impacting torsion angles, pitch, packing arrangements. Through theoretical investigations using density functional theory (DFT) calculations, impact extension aromaticity, planarity distortion, heightened chiral stability were discussed. Photophysical studied through spectrophotometric analysis, insights gained time‐dependent DFT (TD‐DFT) calculations. Following resolution via high‐performance liquid chromatography (HPLC), properties both enantiomers oxa[7]helicene oxa[9]helicene investigated. A slight variation ]helicenes from [7] to [9] induced an approximately three‐fold increase dissymmetry factors biggest values of| g lum | (2.2 × 10 −3 ) compared to| |of (0.8 ), findings discussed supported by TD‐DFT

Язык: Английский

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Synthesis and Functions of Binaphthyl Derivatives with Comprehensive Introduction of Phenylethynyl Groups

Опубликована: Янв. 29, 2024

In this study, compounds with phenylethynyl (PE) groups introduced at all of the possible positions methylene-bridged structure 1,1ʹ-bi-2-naphthol backbone (3-PE to 8-PE) were synthesized. Compounds four or six (3,6-PE, 4,6-PE, 5,6-PE, 6,7-PE, and 3,4,6-PE) also The key reaction for synthesis these was Sonogashira using halogen scaffolds. new transformation methods include (1) selective bromination 5-position binaphthyl skeleton (2) 6-position then iodination 4-position, followed by iodine 4-position lithiation protonation bromine 6-position. optical properties evaluated. extension π system greatly differed depending on position group. 4-PE, 3,4,6-PE, in which extended direction naphthalene linkage axis, showed longer absorption emission wavelengths higher fluorescence quantum yields than other compounds. circularly polarized luminescence measurements, 7-PE a relatively large glum value, an interesting finding that reverses sense.

Язык: Английский

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Synthesis and Optical Properties of Binaphthyl Derivatives with Comprehensive Introduction of Phenylethynyl Groups

Chemistry - An Asian Journal, Год журнала: 2024, Номер 19(15)

Опубликована: Май 25, 2024

In this study, compounds with phenylethynyl (PE) groups introduced at all of the possible positions methylene-bridged structure 1,1'-bi-2-naphthol backbone (3-PE to 8-PE) were synthesized. Compounds four or six (3,6-PE, 4,6-PE, 5,6-PE, 6,7-PE, and 3,4,6-PE) also The key reaction for synthesis these was Sonogashira using halogen scaffolds. new transformation methods include (1) selective bromination 5-position binaphthyl skeleton (2) 6-position then iodination 4-position, followed by iodine 4-position lithiation protonation bromine 6-position. optical properties evaluated. extension π system greatly differed depending on position group. 4-PE, 3,4,6-PE, in which extended direction naphthalene linkage axis, showed longer absorption emission wavelengths higher fluorescence quantum yields than other compounds. circularly polarized luminescence measurements, 7-PE a relatively large g

Язык: Английский

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Enantioselective Synthesis of Benzodihydrofurans Bearing Axial and Central Stereogenic Elements

Chemistry - A European Journal, Год журнала: 2024, Номер 30(69)

Опубликована: Сен. 27, 2024

Abstract The enantioselective synthesis of chiral compounds containing multiple stereogenic elements via a single catalytic step is challenging process. In the presence α‐chloronitrostyrenes and squaramide catalyst, C−C or C−N pro‐axially 2‐naphthol substrates, featuring low barriers to enantiomerization, underwent remote diastereo‐ domino Michael/ O ‐alkylation. It provided desired benzodihydrofurans bearing two carbon atoms configurationally stable bond, thanks high increase barrier rotation upon dihydrofurannulation.

Язык: Английский

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Circularly polarized luminescence and high photoluminescence quantum yields from rigid 5,10-dihydroindeno[2,1-a]indene and 2,2′-dialkoxy-1,1′-binaphthyl conjugates and copolymers

RSC Advances, Год журнала: 2024, Номер 14(11), С. 7251 - 7257

Опубликована: Янв. 1, 2024

Rigid planar carbon-bridged oligo(phenylenevinylene)–binaphthyl conjugates and alternating copolymers exhibit high luminescence quantum yield of >0.95, along with circular polarized dissymmetry factors up to 1.1 × 10 −3 .

Язык: Английский

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Synthesis and Characterization of a Cyclic Trimer of a Chiral Spirosilabifluorene

Chemistry - A European Journal, Год журнала: 2024, Номер 30(45)

Опубликована: Апрель 27, 2024

Abstract A chiral shape‐persistent macrocyclic compound ( Si‐[3] ), designed by the C/Si substitution in spiro‐atom of spirobifluorene cyclic trimer C‐[3] has been successfully synthesized this study. The made spiro‐conjugation and energy levels HOMO LUMO decrease. Due to silicon substitution, was able be degraded fluoride ions, but its reaction rate slower than that unsubstituted spirosilabifluorene, showing chemical stability . Furthermore, chiroptical properties with D 3 ‐symmetric structure were investigated, P , )‐ showed a high emission quantum yield Φ f =80 %) moderate dissymmetry factor circularly polarized luminescence (CPL) g lum,exp =−1.2×10 −3 ). According time‐dependent density‐functional theory (TD‐DFT) calculations using polarizable continuum model (PCM), bright CPL from explained planarization one bisilafluorenyl moiety at excited state, which is responsible for almost fully‐allowed radiative transition short lifetime τ =1.89 ns.

Язык: Английский

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Stereogenic π-Conjugated Macrocycles: Synthesis, Structure, and Chiroptical Properties Including Circularly Polarized Luminescence

Synlett, Год журнала: 2023, Номер unknown

Опубликована: Авг. 22, 2023

Abstract Highly symmetrical and aesthetically pleasing molecules have attracted the attention of organic chemists. We synthesized new highly symmetric stereogenic π-conjugated macrocycles with planar or axial chirality. Macrocyclic oligomers by Yamamoto coupling Suzuki–Miyaura cross-coupling from π-unit containing These cyclization reactions gave multiple in relatively high yields. then elucidated their structures investigated chiroptical properties, including circular dichroism (CD) circularly polarized luminescence (CPL). Because selection rule for rigid structures, these exhibit a dissymmetry factor (g abs g lum) light CD CPL. Several cyclic compounds retain structure excited state higher lum values than common chiral compounds. This Account provides brief background regarding followed summary various this study. are glad if will be source ideas not only chemists working compounds, but also synthetic especially those engaged asymmetric synthesis. 1 Introduction 2 Brief Description Chiroptical Properties 3 Stereogenic Macrocycle Based on [2.2]Paracyclophane 3.1 Double-decker Oligothiophene 3.2 Biselenophene 3.3 Helical Oligophenylene Linked 4 Binaphthyl 4.1 Cyclic Oligomer Chiral 4.2 Doubly Twisted Dimer 4.3 Extended Paraphenylene 4.4 Curved Anchoring 4.5 Binaphthyl-Hinged [5]-Helicene 5 Summary

Язык: Английский

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