Synthesis of an Alternating Polycation with the Dense 1,2,3-Triazole Backbone
In this study, cationic homopolymer and alternating copolymer with the dense triazole backbone were synthesized by copper(I)-catalyzed azide–alkyne cycloaddition polymerization. The polycations obtained were characterized by potentiometric and turbidimetric titrations, and by complex formation with poly(acrylic acid). [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - January 8, 2024 Category: Chemistry Authors: Omae, Tomoki Nakahata, Masaki Kamon, Yuri Hashidzume, Akihito Tags: letter Source Type: research
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Synlett 2024; 35: V- DOI: 10.1055/s-0043-1763662 Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents (Source: Synlett)
Source: Synlett - January 8, 2024 Category: Chemistry Tags: table of contents Source Type: research
Visible-Light-Mediated Selective Allylic C –H Oxygenation of Cycloalkenes
Synlett DOI: 10.1055/a-2219-6907 A visible-light-mediated selective allylic C–H bond oxygenation of cyclic olefins is presented. Hence, the selective, mild monooxygenation of simple cycloalkenes has been achieved using an acridinium photoredox catalyst in combination with a phosphate base and a disulfide HAT reagent under air atmosphere at room temperature. The combination of both photocatalyst and HAT reagent, which can operate through a single or two different concurrent mechanistic pathways for the formation of the allyl radical, proved highly efficient, while the reaction with exclusively one or the other mediator pe...
Source: Synlett - January 5, 2024 Category: Chemistry Authors: Rohlfs, Tabea Gerken, Leon Nova-Fern ández, Jose L. Malag ón, Sara Uygur, Mustafa Cabrera, Silvia Alem án, José Manche ño, Olga García Tags: letter Source Type: research
Organocatalytic, Chemoselective, and Stereospecific House –Meinwald Rearrangement of Trisubstituted Epoxides
We present a novel method for the chemoselective House–Meinwald rearrangement of trisubstituted epoxides under mild conditions with the use of simple perfluorinated disulfonimides as Brønsted acid catalysts. We isolated the α-quaternary aldehyde products in yields of 27–97% using catalyst loadings as low as 0.5 mol% on a scale of 1 mmol. In addition, we show the stereospecific rearrangement using an enantioenriched substrate, which makes this method suitable for applications in total synthesis of natural products. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Ta...
Source: Synlett - January 5, 2024 Category: Chemistry Authors: Dressler, Friedemann Öhler, Victoria Topp, Christopher Schreiner, Peter R. Tags: letter Source Type: research
Synthesis of the C1 –C13 Segment of Poecillastrin C
Synlett DOI: 10.1055/a-2221-9502 A stereoselective synthesis of the C1–C13 segment of poecillastrin C has been achieved. The C1–C4 moiety was derived from diallyl l-tartrate, and the amide group at the C3 position was constructed by means of a traceless Staudinger reaction. The C1–C13 segment was submitted to model studies, including esterification with a bulky alcohol at the C1 position and Stille coupling with vinyl iodide at the C13 position. The reactivity of the C1 position was affected by the neighboring C2-protective group. When the C2 hydroxy group was protected as a TBS ether, the C1 carboxylic acid did not ...
Source: Synlett - January 5, 2024 Category: Chemistry Authors: Clark, Hugh Hosokawa, Seijiro Tags: letter Source Type: research
PhI(OAc)2-Promoted Regioselective Cycloaddition of N-Aminopyridinium Ylides with Electron-Deficient Alkenes
Synlett DOI: 10.1055/a-2216-4594 Herein, we report a regioselective cycloaddition strategy of N-aminopyridinium ylides with electron-deficient alkenes, in the presence of a hypervalent iodine reagent, PhI(OAc)2. A variety of multifunctionalized pyrazolo[1,5-a]pyridine architectures were smoothly afforded by the reactions of pyridine-, quinoline-, and isoquinoline-based N-ylides with diverse alkenes with or without a halogen atom adjacent to the electron-withdrawing group (EWG) under facile conditions. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents ...
Source: Synlett - January 4, 2024 Category: Chemistry Authors: Wang, Junlei Chen, Guiling Shi, Chengcheng Xie, Qinglin Gao, Guocheng Li, Yanan Du, Haijun Cai, Xiaohua Li, Hongqing Huang, Binbin Tags: letter Source Type: research
Thermally Stable Monoruthenium Acetylide Radical Species
Synlett DOI: 10.1055/s-0042-1751538 Control of radical reactivity is regarded as an important concern in the fields of catalysis and materials sciences. Radical species generated from monoruthenium acetylide complexes are, in general, highly reactive, and therefore structural characterization of these species has remained elusive. In this paper, a spectroscopic and structural characterization of the cationic radical species of a monoruthenium diacetylide bearing a Ru tetraphosphine fragment, [trans-(Ar–SC≡C)2Ru(dppe)2]SbCl6 ([1]+SbCl6) [Ar: p-t-BuC6H4; dppe: 1,2-bis(diphenylphosphino)ethane], is presented. The formatio...
Source: Synlett - January 4, 2024 Category: Chemistry Authors: Tanaka, Yuya Yashiro, Atsushi Akita, Munetaka Tags: letter Source Type: research
Update of the Imine-Anion-Mediated Smiles Rearrangement: Application to Migration of Electron-Neutral/Rich Aromatic Groups
Synlett DOI: 10.1055/a-2219-5767 We have revisited the imine-anion-mediated Smiles rearrangement for the synthesis of ortho-hydroxyphenyl arylketimines. Detailed examinations revealed that migration of various aromatic groups, previously considered to be unsuited to SNAr-type reactions, such as electron-rich or sterically hindered aromatic groups, can be accomplished by introducing bulky 9-anthryllithium as a nucleophile. Among the aromatic groups examined, naphthyl groups (1- and 2-naphthyl groups) exhibited an excellent performance, and their migration ability was well illustrated by the reaction with less bulky nucleoph...
Source: Synlett - January 4, 2024 Category: Chemistry Authors: Jinno, Shunki Kawasaki-Takasuka, Tomoko Mori, Keiji Tags: letter Source Type: research
Base-Promoted [3+2] Annulation of Carbodiimides with Diazoacetonitrile for Synthesis of 5-Amino-4-cyano-1,2,3-triazoles
Synlett DOI: 10.1055/a-2216-4765 1,2,3-Triazoles are a privileged class of heterocycles in medicinal and agrochemical science. Here, we describe the base-promoted [3+2] annulation of carbodiimides with diazoacetonitrile. This reaction protocol permits access to a variety of novel 5-amino-4-cyano-1,2,3-triazoles in a regiospecific manner. Further derivatization is exemplified by a skeletal rearrangement and an N-functionalization of triazole products. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - January 3, 2024 Category: Chemistry Authors: Zhou, Lu-Nan Zhang, Fa-Guang Cheung, Chi Wai Ma, Jun-An Tags: letter Source Type: research
FeCl3-Catalyzed Aerobic Oxidative Degradation of Polystyrene to Benzoic Acid: Scope and Mechanism
Synlett DOI: 10.1055/a-2201-3964 Chemical upcycling of polystyrene (PS) is one of the most promising approaches to plastic waste reuse and to achieve economic development goals. However, it remains a huge challenge because PS has only chemically inert covalent bonds. As part of an ongoing study, we herein describe the development, scope, and mechanism of photoinduced iron catalysis for the selective oxidative degradation of polystyrene to benzoic acid. A series of commonly found polystyrene products could be degraded to benzoic acid efficiently. A plausible mechanism involving radical-based stepwise aerobic oxidation was p...
Source: Synlett - January 3, 2024 Category: Chemistry Authors: Zhang, Guoxiang Xue, Ting Wang, Liting Wang, Sichang Ke, Congyu Zeng, Rong Tags: letter Source Type: research
Synthesis of Nitrogen- and Oxygen-Containing Heterocycles Catalysed by Metal Nanoparticles Reported in 2022
Synlett DOI: 10.1055/s-0042-1751533 The versatility of aza- and oxa-heterocyclic compounds has garnered significant attention in recent times. A large number of currently approved pharmaceutical products include nitrogen- and oxygen-containing heterocycles. Recent nanotechnological developments have propelled an upsurge in the applications of nanocatalysis for heterocyclic synthesis. Metal nanoparticles (MNPs) have emerged as promising catalysts for the synthesis of aza- and oxa-heterocycles owing to their unique physicochemical properties. Various MNPs including gold, silver, nickel and palladium have been evaluated for t...
Source: Synlett - January 3, 2024 Category: Chemistry Authors: Dhameliya, Tejas M. Shah, Disha D. Shah, Aayushi C. Shah, Tithi S. Patel, Tanvi M. Rana, Devalben K. Sureja, Dipen K. Bodiwala, Kunjan B. Tags: account Source Type: research
Defluorinative Asymmetric Allylic Alkylations
Synlett DOI: 10.1055/a-2211-6538 The introduction of allyl fluorides as alternative electrophiles in asymmetric allylic alkylation reactions has recently attracted significant interest. Despite the intrinsic thermodynamically demanding C–F bond-cleavage event, the fluorophilic nature of the silicon atom is key in assisting the activation and cleavage of the allylic C–F bond. Thus, the use of silylated compounds as unconventional nucleophiles, together with the Lewis basicity of fluorine when acting as a leaving group, enables the development of innovative chemical transformations within mild and selective catalytic sch...
Source: Synlett - January 2, 2024 Category: Chemistry Authors: Rodr íguez, Paula Duran, Jordi Gisbert, Mart í Company ó, Xavier Tags: synpacts Source Type: research
Visible-Light-Induced Three-Component Radical Coupling of Selenocarbamates, Enones, and Allylstannanes with Diphenyl (2,4,6-trimethylbenzoyl)phosphine Oxide
Synlett DOI: 10.1055/a-2214-5512 A blue LED-induced three-component coupling of a carbamoyl radical, cyclic enone, and allylstannane was developed. The use of blue LEDs and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a radical initiator permitted the three-component radical coupling to proceed with a high chemoselectivity. An elucidation of the mechanism revealed a pathway for the formation of a tributyltin radical from TPO and allylstannane. This tandem radical reaction is expected to be applicable in natural-product synthesis. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle i...
Source: Synlett - December 21, 2023 Category: Chemistry Authors: Komine, Keita Yamazaki, Yuta Iwanaga, Taiga Sakaguchi, Hikaru Fukuda, Hayato Ishihara, Jun Tags: letter Source Type: research
Synthesis of 2 ′-Deoxy-2′-β-fluoro-4′-azido-5-fluorouridine as a Potential Anti-HIV Agent
Synlett DOI: 10.1055/a-2213-2408 2′-Deoxy-2′-β-fluoro-4′-azido-5-fluorouridine, a new pyrimidine nucleoside analogue of azvudine (FNC), was designed and synthesized. The synthesis of this nucleoside analogue was achieved by bromination of 1,3,5-O-tribenzoyl-2-deoxy-2-fluoro-d-arabinofuranoside, followed by reaction with silylated 5-fluorouracil and further modifications of the sugar moiety, in a 7.6% overall yield over nine steps. The product exhibited good antiviral activity against HIV-1 infection in HEK293T cells. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals...
Source: Synlett - December 21, 2023 Category: Chemistry Authors: Hou, Jiao Wang, Jian-Hua Yu, Wenquan Chang, Junbiao Tags: letter Source Type: research
Photocatalytic [2,3]-Sigmatropic Rearrangement Reactions of Ethyl Diazoacetate
We describe a photocatalytic reaction of diazo compounds with allyl sulfides under visible-light reaction conditions. In the presence of Ru(bpy)3Cl2 as a photocatalyst, a [2,3]-sigmatropic rearrangement reaction occurs that leads to the formation of homoallylic sulfides. This reaction proceeds in acetone as the solvent, which is unusual in carbene-transfer reactions, and it shows a broad substrate scope in the rearrangement reaction of allylic sulfides. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - December 20, 2023 Category: Chemistry Authors: M. Bopape, Karabo Shah, Aryan Koenigs, Rene M. Tags: letter Source Type: research
