Alkene versus Aryl Chlorination in Asymmetric Hypervalent Iodine Catalysis: A Case Study
Synlett DOI: 10.1055/a-2201-7326 Hypervalent λ3-iodanes have become a prominent tool for halofunctionalizations of alkenes. Despite many examples of asymmetric fluorinations reported lately, the corresponding enantioselective chlorination reactions using iodoresorcinol-based catalysts are significantly less developed, with only one example known to date. Here, we show how competing aromatic chlorination of the iodoarene catalyst is a significant obstacle in these transformations, hinting towards a conceptual issue with this well-established catalyst class for enantioselective chlorinations. Consequently, the reaction cond...
Source: Synlett - December 6, 2023 Category: Chemistry Authors: Arnold, Andreas M. Binder, Julia Kretzschmar, Martin Gulder, Tanja Tags: letter Source Type: research
Regio- and Stereoselective Synthesis of 2 ′-Deoxy-4′-thioguanine Nucleosides: Evaluation of Anti-Hepatitis B Virus Activity and Cytotoxicity Leading to Improved Selectivity Index by 4′-C-Cyanation
Synlett DOI: 10.1055/s-0043-1763629 An N
9-regio- and β-anomer-selective 4′-thioglycosidation of purine bases has been developed. The reaction between a 2-deoxy-2-iodo-4-thioribofuranosyl glycosyl donor and N-(6-chloro-9H-purin-2-yl)-2-methylpropanamide gave the corresponding 2′-deoxy-4′-thiopurine nucleoside in 87% yield along with its N
7-regioisomer in 6% yield, without the formation of the α-anomer. By using a derivative obtained from 17, a practical chemical synthesis of 2′-deoxy-4′-thioguanosine was developed. 4′-α-C-Cyano-2′-deoxy-4′-thioguanosine was synthesized, starting from a 4-(ac...
Source: Synlett - December 5, 2023 Category: Chemistry Authors: Kumamoto, Hiroki Imoto, Shuhei Kuwata-Higashi, Nobuyo Mitsuya, Hiroaki Haraguchi, Kazuhiro Tags: letter Source Type: research
Quinolinamide-Enabled Nickel-Catalyzed Regio- and Diastereoselective γ,δ-Arylalkylation of Nonactivated Alkenes
Synlett DOI: 10.1055/a-2192-7085 A quinolinamide-enabled nickel-catalyzed γ,δ-arylalkylation of homoallylic amines with aryl iodides and organozinc compounds has been developed. The cleavable quinolinamide directing group facilitates the stabilization of a five-membered nickelacycle, and enables the dicarbofunctionalization of nonactivated alkenes with excellently regio-, chemo-, and diastereoselectivity. The reaction with internal alkenes proceeds stereospecifically to provide valuable γ-alkyl-δ-aryl-substituted amines with two vicinal stereocenters. The scope of substrates and the utility of the protocol have been th...
Source: Synlett - December 4, 2023 Category: Chemistry Authors: Zhang, Lanlan Zhao, Lei Zhu, Yuqin Wang, Chao Tags: letter Source Type: research
Internal Atom Exchange in Oxazole Rings: A Blueprint for Azole Scaffold Evaluation
Synlett DOI: 10.1055/a-2201-9285 In this article, we provide a route to transform isoxazoles and oxadiazoles into the corresponding pyrazoles and 1,2,4-triazoles in one step using catalytic amounts of an air-stable Ni(0) complex. The reaction is a formal atom-exchange process at the internal heteroatoms of the aromatic cycle. This work provides a blueprint for reactivity that permits the rapid evaluation of different five-membered azole scaffolds, thus avoiding de novo synthesis of the molecule of interest. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of conten...
Source: Synlett - December 4, 2023 Category: Chemistry Authors: Spinnato, Davide Leutzsch, Markus Wang, Feng Cornella, Josep Tags: letter Source Type: research
Synthesis and Evaluation of 3 ′-Oleyl–Oligonucleotide Conjugates as Potential Cellular Uptake Enhancers
Synlett DOI: 10.1055/s-0042-1751528 The field of therapeutic oligonucleotides has experienced significant growth in recent years, both in terms of approved drugs and those undergoing clinical trials. This expansion has transformed it into a rapidly evolving area of research. However, their cellular internalization remains a major limitation for the clinical application of oligonucleotides. To address this limitation, we report different strategies for the synthesis of specialized solid supports for the direct synthesis of 3′-oleyl-oligonucleotides by means of an l-threoninol derivative. A series of in vitro cell experime...
Source: Synlett - December 1, 2023 Category: Chemistry Authors: Navarro, Natalia Serantes, Sergio Avi ñó, Anna F àbrega, Carme Eritja, Ramon Tags: letter Source Type: research
Lewis Base/3d Transition-Metal Cooperatively Catalyzed Asymmetric Reactions
Conclusion [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - December 1, 2023 Category: Chemistry Authors: Song, Jin Gong, Liu-Zhu Tags: account Source Type: research
Methods for the Synthesis of 1-Indanones Containing a β-Quaternary Carbon Center
This article traces the development of synthetic routes toward 1-indanones containing a β-quaternary carbon center. The recent advancement in the regio- and chemoselective formal (4+1) carbocyclization of chalcones with internal alkynes via rhodium(III) catalysis for the synthesis of 1-indanones is highlighted. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Song, Shuaishuai Zhou, Wang Tags: synpacts Source Type: research
A Simplified Protocol for Large-Scale Preparation of 4CzIPN and 3DPA2FBN
Synlett DOI: 10.1055/s-0042-1751523 Just in the past few years, the application of 4CzIPN as a photocatalyst in photochemistry has been dramatically increased with its unique properties. In the literature, a variety of protocols for the synthesis of 4CzIPN have been reported. However, a practical process for the preparation of 4CzIPN with consistent quality on large scale is not available, but highly desirable to enable the robust application of this photocatalysis in industry. Herein, we detailed a practical and simple column-free chemical process amenable for the large-scale production of 4CzIPN with high quality in 91% ...
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Zhang, Yongda Lei, Zhen Xu, Yibo Kosnik, Stephanie C. Jiang, Qi Tags: letter Source Type: research
Enantioselective Sulfonation of Enones with Sulfinates by Thiourea/Tertiary-Amine Catalysis
Synlett DOI: 10.1055/a-2202-0842 Chiral γ-keto sulfones are significant structures in both organic synthesis and pharmaceutical chemistry. Although there are many choices for obtaining racemic forms, only a few enantioselective methods have been reported. We have developed a simple way for obtaining chiral γ-keto sulfones in moderate yields and moderate enantiomeric ratios. Readily available sulfinates were directly used as substrates that could be converted into sulfinic acids by treatment with boric acid. The bifunctional catalyst forms a chiral ion pair with the sulfinic acid and controls the enantioselectivity of the...
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Wang, Si-fan Yan, Ming Shi, Jin-yi Li, Guang-xun Zhao, Jin-zhong Tags: letter Source Type: research
anti-Selective Synthesis of Substituted β-Homoprolines by Rhodium Alkyl Nitrene C–H Insertion
Synlett DOI: 10.1055/a-2201-7267 A range of β-homoprolines was prepared with high anti-selectivity. An intramolecular C–H insertion reaction involving a rhodium alkyl nitrene is a key step in the ring construction. The carboxylic acid in the products can serve as a springboard for further downstream transformations. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Tang, Xinxin Noda, Hidetoshi Shibasaki, Masakatsu Tags: letter Source Type: research
A Study on the Diazo-Transfer Reaction Using o-Nitrobenzenesulfonyl Azide
We present a study on the diazo-transfer reaction using o-nitrobenzenesulfonyl azide (o-NsN3). o-NsNN15N, a γ-15N-labeled diazo-transfer reagent, was newly developed and found to be better than TfNN15N with respect to its physicochemical properties and ease of synthesis. Unlike TfNN15N, however, o-NsNN15N was found to afford a mixture of β- and γ-15N-labeled azides rather than the β-15N-labeled azide alone. A mechanism for the diazo-transfer reaction of o-NsNN15N with primary amines is proposed to explain the formation of such isotopomeric mixtures. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germ...
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Gwak, Sungduk Lee, Ji Hye Kwon, Hyeok-Jun Han, Hogyu Tags: letter Source Type: research
Remote Enantioselective Epoxidation Reactions Catalyzed by Chiral Iron Porphyrin Complexes with a Hydrogen-Bonding Site
Synlett DOI: 10.1055/s-0042-1751527 Iron porphyrin complexes, which were linked via a para-phenylethynyl group to a chiral scaffold with a lactam binding site, were probed as catalysts in the enantioselective epoxidation of 4-(ω-alkenyl)-quinolones. It was found that the 3-butenyl group in the substrate accounts for the highest enantioselectivity (up to 44% ee) and the absolute configuration of an oxirane product was elucidated by electron diffraction. A two-point hydrogen bond of the substrate to the catalyst is likely responsible for enantioface differentiation at a remote position. The study shows chirality transfer to...
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Ahmed, Hussayn P öthig, Alexander Truong, Khai-Nghi Bach, Thorsten Tags: letter Source Type: research
[4+1] Cyclizations to Enantiopure Multifunctional Cyclopentanes from d-Glucose Using Formyl Dianion Synthons
Synlett DOI: 10.1055/a-2201-3861 The [4+1] cyclization of a sugar-based epoxytosylate with various C1 dianion equivalents provide highly functionalized homochiral cyclopentane derivatives. For these, a follow-up chemistry was developed to provide various cyclopentane building blocks as starting points for natural product syntheses. The [4+1] domino protocol relies on a 1,4-Brook rearrangement, which is essential for generating the second carbanion. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Oelze, Silke Br äuer, Nico Michel, Tycho Schaumann, Ernst Kirschning, Andreas Tags: cluster Source Type: research
Practical Fischer Indolization Using Bench-Stable Arylhydrazine Sulfonate as the Surrogate of Arylhydrazine
Synlett DOI: 10.1055/s-0043-1763622 Fischer indolization using bench-stable sodium arylhydrazine sulfonate as a surrogate of arylhydrazine was developed. The preparation of arylhydrazine sulfonate was also modified by replacing sodium sulfite reductant with Pd-catalyzed hydrogen transfer. The straightforward synthesis of tetrahydrocarbazoles from the corresponding anilines was successfully conducted in a one-pot manner. A practical application of this method was demonstrated in the formal synthesis of pharmaceutical molecules Rizatriptan and Zolmitriptan. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Ge...
Source: Synlett - November 30, 2023 Category: Chemistry Authors: Li, Wenjuan Shen, Chaoren Zhu, Yanping Dong, Kaiwu Tags: cluster Source Type: research
Linked PDF of Table of Contents
Synlett 2023; 34: VII- DOI: 10.1055/s-0043-1763654 Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents (Source: Synlett)
Source: Synlett - November 29, 2023 Category: Chemistry Tags: table of contents Source Type: research
