Tetrahedron chemPub Date : 2024-09-26DOI: 10.1016/j.tchem.2024.100095
Zhuo Wang , Chunngai Hui , Hu Wang
{"title":"Synthesis of spiro[4.4]nonane-containing functional organic molecules","authors":"Zhuo Wang , Chunngai Hui , Hu Wang","doi":"10.1016/j.tchem.2024.100095","DOIUrl":"10.1016/j.tchem.2024.100095","url":null,"abstract":"<div><div>Spiro[4.4]nonane features are an important scaffold in many applications such as enantioenriched ligands, functional materials, natural products, and polymers. Excited by the prospect of the spiro[4.4]nonane scaffold, its structural intricacy still appears challenging in chemical synthesis. Many functional organic molecules possessing spiro[4.4]nonane scaffold(s) have recently been reported and synthesized. We provide a <em>Minireview</em> highlighting such advancements and discuss the future opportunities of spiro[4.4]nonane scaffolds in organic chemistry. Representative examples from 2019 to 2024 are discussed.</div></div>","PeriodicalId":74918,"journal":{"name":"Tetrahedron chem","volume":"12 ","pages":"Article 100095"},"PeriodicalIF":0.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetrahedron chemPub Date : 2024-09-10DOI: 10.1016/j.tchem.2024.100092
Maciej Dajek , Mikołaj J. Janicki , Paulina D. Kubiak , Julia Bąkowicz , Błażej Dziuk , Rafał Kowalczyk
{"title":"Betaketothioesters in organocatalysis: Harnessing nucleophilic reactivity, the fluorophobic effect, and expanding the substrate repertoire","authors":"Maciej Dajek , Mikołaj J. Janicki , Paulina D. Kubiak , Julia Bąkowicz , Błażej Dziuk , Rafał Kowalczyk","doi":"10.1016/j.tchem.2024.100092","DOIUrl":"10.1016/j.tchem.2024.100092","url":null,"abstract":"<div><p>The use of thioesters as nucleophiles marks a considerable change in organic synthesis. This new method, propelled by gentle enolization with minimal catalyst loading, results in enantiomeric excesses surpassing 95 % under ambient conditions, accomplishing total conversion in merely 6 h. Remarkably, this method eliminates the need for additional functional groups in nitroalkenes for efficient chirality transfer from the organocatalyst. The exceptional reactivity of thioesters, combined with their water tolerance, enables reactions utilizing the hydrophobic effect, resulting in reaction times as short as 15 min and products with slightly enhanced stereoselectivity compared to analogous reactions in dichloromethane. Additionally, reactions performed in perfluorinated solvents outpace their homogenous counterparts in organic solvents, delivering products in shorter time with comparable stereoselectivity. This work highlights the rare utilization of the fluorous effect in organocatalysis. Simple squaramides also exhibit remarkable catalytic activity in the reactions of beta-keto thioesters with alpha-bromo nitroalkenes. As little as 0.1 mol% of the catalyst leads to product formation with an 86 % yield (qNMR) and 93 % enantiomeric excess. Upscaling the reaction does not significantly affect the enantiomeric excess but leads to a slight decrease in yield from 82 % to 77 %. It has been demonstrated that thioesters react more rapidly than their ketoester counterparts, and the two-step reaction leading to dihydrofuran ring closure is entirely accomplished by extending the reaction time, eliminating the need for additional base. The examples presented here expand the range of substrates derived from carboxylic acid esters in catalytic reactions, suggesting the potential for the synthesis of challenging reactions in analogs of alkoxyl esters. Additional KS-DFT calculations shed more light on the reaction paths, rationalizing the observed stereochemical outcomes.</p></div>","PeriodicalId":74918,"journal":{"name":"Tetrahedron chem","volume":"12 ","pages":"Article 100092"},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666951X24000317/pdfft?md5=e8c77ccd308b186191ed4d3a27f7cdfd&pid=1-s2.0-S2666951X24000317-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Palladium-catalyzed desymmetric coupling reaction between silacyclobutanes and terminal alkynes for the synthesis of silicon-stereogenic allyl vinylsilanes","authors":"Zhi-Yuan Chen , Zi-Lu Wang , Jin-Bo Zhao , Yun-He Xu","doi":"10.1016/j.tchem.2024.100093","DOIUrl":"10.1016/j.tchem.2024.100093","url":null,"abstract":"<div><div>A palladium/TADDOL-derived phosphonate catalyzed desymmetric ring-opening coupling bewteen prochiral silacyclobutanes and alkyl terminal alkynes was developed. This catalytic system facilitates the formation of optically active allyl vinylsilane compounds featuring a quaternary silicon-stereogenic center, achieving good to high yields and moderate to good enantiomeric ratios. This approach significantly broaden the scope of ring-opening desymmetrization reactions involving silacyclobutanes under transition metal catalysis.</div></div>","PeriodicalId":74918,"journal":{"name":"Tetrahedron chem","volume":"12 ","pages":"Article 100093"},"PeriodicalIF":0.0,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666951X24000329/pdfft?md5=073e3035c3d6920f145a27af2ba1c7ee&pid=1-s2.0-S2666951X24000329-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetrahedron chemPub Date : 2024-08-18DOI: 10.1016/j.tchem.2024.100091
Timofey P. Martyanov , Artem P. Vorozhtsov , Evgeny N. Ushakov , Nikita A. Slesarenko , Ilia V. Sulimenkov , Sergey P. Gromov
{"title":"Self-assembly via hydrogen bonding of bis(18-crown-6)-1,3-distyrylbenzene and [2 + 2] photocycloaddition: Stereoselective synthesis of [2.2]metacyclophanes and butterfly-type thermal isomerization","authors":"Timofey P. Martyanov , Artem P. Vorozhtsov , Evgeny N. Ushakov , Nikita A. Slesarenko , Ilia V. Sulimenkov , Sergey P. Gromov","doi":"10.1016/j.tchem.2024.100091","DOIUrl":"10.1016/j.tchem.2024.100091","url":null,"abstract":"<div><p>The photochemistry of bis(18-crown-6)-containing 1,3-distyrylbenzene and its 2 : 2 bis-pseudo-sandwich complex with ethane-1,2-diammonium was studied. The UV irradiation of the supramolecular complex resulted in the formation of three geometric isomers of tetracrown-containing dicyclobutano[2.2]metacyclopane, differing in the orientation of the cyclobutane moieties, with the unsymmetrical isomer (>50 %) predominating. The diammonium cations used as the template could be removed after photolysis by simple extraction, and the product was obtained in high yield (82 %). The <sup>1</sup>H NMR signals of a mixture of geometric isomers of [2.2]metacyclophane derivative were assigned resorting to quantum chemistry methods (DFT). The kinetic and thermodynamic parameters of thermal isomerization between the <em>endo</em>,<em>endo</em>- and <em>exo</em>,<em>exo</em>-isomers were measured. Tetracrown-containing dicyclobutano[2.2]metacyclophanes are homotetratopic ligands that contain four binding sites for metal and ammonium cations, which is of interest for the design of photo- and thermo-switchable supramolecular devices with a variable complex formation behavior and supramolecular machines owing to the butterfly-type thermal isomerization.</p></div>","PeriodicalId":74918,"journal":{"name":"Tetrahedron chem","volume":"12 ","pages":"Article 100091"},"PeriodicalIF":0.0,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666951X24000305/pdfft?md5=bbc61009297f58bea762604b4ff7acfe&pid=1-s2.0-S2666951X24000305-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetrahedron chemPub Date : 2024-08-15DOI: 10.1016/j.tchem.2024.100089
Samuel Redl, Christoph Topf
{"title":"(Semi)hydrogenation of enoates and alkynes effected by a versatile, particulate copper catalyst","authors":"Samuel Redl, Christoph Topf","doi":"10.1016/j.tchem.2024.100089","DOIUrl":"10.1016/j.tchem.2024.100089","url":null,"abstract":"<div><p>We communicate a versatile and user-friendly Cu-based catalytic method that allows for the selective hydrogenation of enoates and alkynes. The introduced protocol is free from any ex ante modifications of the used Cu(I) precursors by air-sensitive phosphines or elaborate <em>N</em>-heterocyclic carbene ligands. The conjugate hydrogenation of enoates and the (selective) reduction of C<img>C bonds is achieved through a [Cu(CH<sub>3</sub>CN)<sub>4</sub>]<sup>+</sup>/<em>tert</em>-butoxide pair whereby we describe a delicate influence of the base cation on the chemoselectivity of the respective transformation. In case of the ester-to-alcohol reduction, a combination of simple CuI and NaO<em>t</em>Bu proved to be successful. Deuteration experiments are included to address certain mechanistic aspects of the introduced catalytic system. All requisite chemicals are readily obtainable through commercial channels and the catalyst assembly is set up on the bench without the need for special lab-technical precautions.</p></div>","PeriodicalId":74918,"journal":{"name":"Tetrahedron chem","volume":"12 ","pages":"Article 100089"},"PeriodicalIF":0.0,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666951X24000287/pdfft?md5=5437e19b8968da8070a19157b748e4dc&pid=1-s2.0-S2666951X24000287-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}