Pub Date : 2025-03-29DOI: 10.1016/j.tetlet.2025.155566
Bing Han , Yuge Ji , Jing Qin , Lei Liu , Gang Wang
An efficient manganese-catalyzed cross-dehydrogenative coupling of thiols and P(O)H compounds with air as the oxidant has been established. This simple and green system has a good substrate scope and functional group tolerance. Aryl and alkyl thiols worked well with P(O)H compounds to produce the corresponding thiophosphates in good to excellent yields.
{"title":"Manganese-catalyzed aerobic cross-dehydrogenative coupling of thiols with P(O)H compounds","authors":"Bing Han , Yuge Ji , Jing Qin , Lei Liu , Gang Wang","doi":"10.1016/j.tetlet.2025.155566","DOIUrl":"10.1016/j.tetlet.2025.155566","url":null,"abstract":"<div><div>An efficient manganese-catalyzed cross-dehydrogenative coupling of thiols and P(<em>O</em>)H compounds with air as the oxidant has been established. This simple and green system has a good substrate scope and functional group tolerance. Aryl and alkyl thiols worked well with P(<em>O</em>)H compounds to produce the corresponding thiophosphates in good to excellent yields.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155566"},"PeriodicalIF":1.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1016/j.tetlet.2025.155550
Takanori Shibata, Ryo Tokutake, Mamoru Ito
Markovnikov-selective hydrothiolation of tri- and tetrasubstituted alkenes proceeds at room temperature to give various tertiary sulfides. Aryl- and alkyl-substituted alkenes, including cyclic ones, are viable substrates. In addition to alkyl and aryl thiols, thioacetic acid is also available.
{"title":"TfOH-catalyzed Markovnikov-selective hydrothiolation of tri- and tetrasubstituted alkenes","authors":"Takanori Shibata, Ryo Tokutake, Mamoru Ito","doi":"10.1016/j.tetlet.2025.155550","DOIUrl":"10.1016/j.tetlet.2025.155550","url":null,"abstract":"<div><div>Markovnikov-selective hydrothiolation of tri- and tetrasubstituted alkenes proceeds at room temperature to give various tertiary sulfides. Aryl- and alkyl-substituted alkenes, including cyclic ones, are viable substrates. In addition to alkyl and aryl thiols, thioacetic acid is also available.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"160 ","pages":"Article 155550"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143714899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1016/j.tetlet.2025.155567
Mahshid Attarroshan, Bryan Chacon Vazquez, Caden R. Andrews, Sean L. Stokes, Joseph P. Emerson
A copper-catalyst system for the chemoselective reduction of electronically diverse chalcones under mild reaction conditions is reported here. This straightforward method employs phenylsilane (PhSiH3) as a mild hydride source, 4,5-diazafluoren-9-one (DAFO) as a ligand, and copper(II) acetate as the catalyst. The reduction was successfully applied to a range of chalcone derivatives containing both electron-donating (EDG) and electron-withdrawing (EWG) groups. Under optimized conditions, a broad scope of substrates was explored, yielding products in moderate to good yields. The sustainability of copper catalysis and the ease of applying this catalytic system make it an attractive alternative for selective alkene reductions in targeted organic synthesis.
{"title":"Copper(II)-catalyzed selective reduction of chalcones using phenylsilane","authors":"Mahshid Attarroshan, Bryan Chacon Vazquez, Caden R. Andrews, Sean L. Stokes, Joseph P. Emerson","doi":"10.1016/j.tetlet.2025.155567","DOIUrl":"10.1016/j.tetlet.2025.155567","url":null,"abstract":"<div><div>A copper-catalyst system for the chemoselective reduction of electronically diverse chalcones under mild reaction conditions is reported here. This straightforward method employs phenylsilane (PhSiH<sub>3</sub>) as a mild hydride source, 4,5-diazafluoren-9-one (DAFO) as a ligand, and copper(II) acetate as the catalyst. The reduction was successfully applied to a range of chalcone derivatives containing both electron-donating (EDG) and electron-withdrawing (EWG) groups. Under optimized conditions, a broad scope of substrates was explored, yielding products in moderate to good yields. The sustainability of copper catalysis and the ease of applying this catalytic system make it an attractive alternative for selective alkene reductions in targeted organic synthesis.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155567"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1016/j.tetlet.2025.155569
Lei Wang, Ming-Jun Li, Qing-Hai Li, Peng Xu, Si-Qi Chen, Hui Xu, Ze Zhang
Under ball-milling and heating conditions, the cascade cyclization of arylidene isoxazolones with β‑carbonyl esters proceeded smoothly in the presence of catalytic amount of FeBr3, affording polysubstituted pyridines in moderate to excellent (68ￚ93%) yields. A plausible reaction mechanism involving Michael addition, isoxazolone ring-opening, decarboxylation, and dehydration-driven aromatization was proposed. This mechanochemical protocol offers advantages such as high atom economy, solvent-free conditions and scalability making it a sustainable alternative for pyridine synthesis.
{"title":"Mechanosynthesis of polysubstituted pyridines via FeBr3-catalyzed cascade reaction of arylidene isoxazolones with β‑carbonyl esters","authors":"Lei Wang, Ming-Jun Li, Qing-Hai Li, Peng Xu, Si-Qi Chen, Hui Xu, Ze Zhang","doi":"10.1016/j.tetlet.2025.155569","DOIUrl":"10.1016/j.tetlet.2025.155569","url":null,"abstract":"<div><div>Under ball-milling and heating conditions, the cascade cyclization of arylidene isoxazolones with β‑carbonyl esters proceeded smoothly in the presence of catalytic amount of FeBr<sub>3</sub>, affording polysubstituted pyridines in moderate to excellent (68ￚ93%) yields. A plausible reaction mechanism involving Michael addition, isoxazolone ring-opening, decarboxylation, and dehydration-driven aromatization was proposed. This mechanochemical protocol offers advantages such as high atom economy, solvent-free conditions and scalability making it a sustainable alternative for pyridine synthesis.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155569"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1016/j.tetlet.2025.155563
Hong Cao , Hui Liu , Jin-Xi Liao , Jian-Song Sun
Abstract
With glycosyl tetrafluoropyridin-4-yl thioglycosides (TFPTGs) as radical glycosylation donors, protocols to furnishing C-, O-, and N-glycosides have been established. TFPTGs represent the first type of donors amenable to forge both C- and O-/N-glycosidic linkages under light irradiation through radical glycosylation. For C- and O-glycosides, α-stereoselectivity was secured due to the stereoelectronic effect, while N-glycosides were obtained β-stereoselectively presumably because of in situ epimerization.
{"title":"Tetrafluoropyridin-4-yl thioglycosides (TFPTGs): Versatile donors in C-, O-, and N-glycosidic construction","authors":"Hong Cao , Hui Liu , Jin-Xi Liao , Jian-Song Sun","doi":"10.1016/j.tetlet.2025.155563","DOIUrl":"10.1016/j.tetlet.2025.155563","url":null,"abstract":"<div><div>Abstract</div><div>With glycosyl tetrafluoropyridin-4-yl thioglycosides (TFPTGs) as radical glycosylation donors, protocols to furnishing <em>C</em>-, <em>O</em>-, and <em>N</em>-glycosides have been established. TFPTGs represent the first type of donors amenable to forge both <em>C</em>- and <em>O</em>-/<em>N</em>-glycosidic linkages under light irradiation through radical glycosylation. For <em>C</em>- and <em>O</em>-glycosides, α-stereoselectivity was secured due to the stereoelectronic effect, while <em>N</em>-glycosides were obtained β-stereoselectively presumably because of <em>in situ</em> epimerization.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"160 ","pages":"Article 155563"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gregarithecinol (1), a new trichodiene/bazzanene-type sesquiterpene, was isolated from the fungus Gregarithecium curvisporum KT4079. This compound features a rotatable sp3 linkage connecting both asymmetric cyclohexane and cyclopentane moieties. Consequently, elucidating their configurational relationship using conventional spectral analysis alone was challenging. However, by analyzing multiple observed characteristic spectral profiles in combination with DFT calculations, the relative and absolute configurational relationships between the segments were successfully established, whereas DP4 analysis alone was inconclusive.
{"title":"Gregarithecinol, a trichodiene/bazzanene derivative from Gregarithecium curvisporum KT4079: DFT-supported stereochemical elucidation of units linked by a rotatable bond","authors":"Azuma Murakami , Ryuhi Kanehara , Kazuaki Tanaka , Masaru Hashimoto","doi":"10.1016/j.tetlet.2025.155568","DOIUrl":"10.1016/j.tetlet.2025.155568","url":null,"abstract":"<div><div>Gregarithecinol (<strong>1</strong>), a new trichodiene/bazzanene-type sesquiterpene, was isolated from the fungus <em>Gregarithecium curvisporum</em> KT4079. This compound features a rotatable sp<sup>3</sup> linkage connecting both asymmetric cyclohexane and cyclopentane moieties. Consequently, elucidating their configurational relationship using conventional spectral analysis alone was challenging. However, by analyzing multiple observed characteristic spectral profiles in combination with DFT calculations, the relative and absolute configurational relationships between the segments were successfully established, whereas DP4 analysis alone was inconclusive.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155568"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thionation of tertiary α-diazoamides has been realized by treatment with Lawesson reagent. A variety of 5-amino-1,2,3-thiadiazoles containing secondary amines are made in high to excellent yields.
{"title":"Expedient conversion of tertiary α-diazoamide to 5-amino-1,2,3-thiadiazole through a thionation-cyclization cascade","authors":"Xiao-Jing Tian, Guodong Hu, Mei-Hua Shen, Hua-Dong Xu","doi":"10.1016/j.tetlet.2025.155564","DOIUrl":"10.1016/j.tetlet.2025.155564","url":null,"abstract":"<div><div>Thionation of tertiary α-diazoamides has been realized by treatment with Lawesson reagent. A variety of 5-amino-1,2,3-thiadiazoles containing secondary amines are made in high to excellent yields.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155564"},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-27DOI: 10.1016/j.tetlet.2025.155551
Mariam Mutiu Adebayo, Douglas A. Klumpp
Aromatic imines were prepared from 9-fluorenone and azafluorenones and these substrates were reacted in the Brønsted superacid, triflic acid, to produce good yields of nitrogen-containing spirocycles. A mechanism is proposed involving dicationic, superelectrophilic intermediates. The resulting spirocycles may be easily functionalized at nitrogen to prepared amides, sulfonamides, and other derivatives.
{"title":"Synthesis of nitrogen-containing Spirocycles via Superacid-promoted Cyclizations of imines","authors":"Mariam Mutiu Adebayo, Douglas A. Klumpp","doi":"10.1016/j.tetlet.2025.155551","DOIUrl":"10.1016/j.tetlet.2025.155551","url":null,"abstract":"<div><div>Aromatic imines were prepared from 9-fluorenone and azafluorenones and these substrates were reacted in the Brønsted superacid, triflic acid, to produce good yields of nitrogen-containing spirocycles. A mechanism is proposed involving dicationic, superelectrophilic intermediates. The resulting spirocycles may be easily functionalized at nitrogen to prepared amides, sulfonamides, and other derivatives.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155551"},"PeriodicalIF":1.5,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1016/j.tetlet.2025.155554
Xin Yuan , Xiao-Ping He , Yuan-Liang Xu , Li-Xia Wang , Yan Liu , Kai Guo , Sheng-Hong Li
Four new labdane diterpenoid glycosides, leucanumosides A–D (1–4), were isolated from the leaves and flowers of Leucosceptrum canum. Their structures, sharing an unusual α,β-unsaturated δ-lactone unit, were identified by comprehensive spectroscopic methods, including HRESIMS, NMR, IR, specific rotation, and quantum chemical calculations. The acid hydrolysis method was used to determine the configurations of glycosyl groups. Immunosuppressive assay was performed. Compound 4 exhibited moderate activity against the secretion of cytokines tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in macrophages RAW264.7 induced by lipopolysaccharide (LPS). The plausible biosynthetic pathways for compounds 1–4 were inferred.
{"title":"New labdane diterpenoid glycosides from the leaves and flowers of Leucosceptrum canum","authors":"Xin Yuan , Xiao-Ping He , Yuan-Liang Xu , Li-Xia Wang , Yan Liu , Kai Guo , Sheng-Hong Li","doi":"10.1016/j.tetlet.2025.155554","DOIUrl":"10.1016/j.tetlet.2025.155554","url":null,"abstract":"<div><div>Four new labdane diterpenoid glycosides, leucanumosides A–D (<strong>1</strong>–<strong>4</strong>), were isolated from the leaves and flowers of <em>Leucosceptrum canum</em>. Their structures, sharing an unusual <em>α</em>,<em>β</em>-unsaturated <em>δ</em>-lactone unit, were identified by comprehensive spectroscopic methods, including HRESIMS, NMR, IR, specific rotation, and quantum chemical calculations. The acid hydrolysis method was used to determine the configurations of glycosyl groups. Immunosuppressive assay was performed. Compound <strong>4</strong> exhibited moderate activity against the secretion of cytokines tumour necrosis factor-<em>α</em> (TNF-<em>α</em>) and interleukin-6 (IL-6) in macrophages RAW264.7 induced by lipopolysaccharide (LPS). The plausible biosynthetic pathways for compounds <strong>1</strong>–<strong>4</strong> were inferred.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"161 ","pages":"Article 155554"},"PeriodicalIF":1.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1016/j.tetlet.2025.155560
Ivan A. Kochnev, Nikita S. Simonov, Alexey Y. Barkov
In this work, we demonstrated a novel method for the synthesis of hemicurcuminods. The method is based on the Wittig olefination of aromatic, cinnamic and aliphatic aldehydes with 1-aryl-4-(triphenyl-λ5-phosphanylidene)butane-1,3-diones. This simple protocol has a broad aldehyde scope and great E-selectivity. The main advantage of this method is its ability to synthesize hemicurcuminoids containing acceptor groups and halogens in the styryl fragment with good yields. Hemicurcuminoids were obtained with a yield of up to 85 %. Moreover, this method can be easily scaled up for gram-scale synthesis of a wide scope of aromatic aldehydes.
{"title":"(E)-selective syntheses of Hemicurcuminoids/Styryl diketones by Wittig olefination of aromatic, cinnamic and aliphatic aldehydes","authors":"Ivan A. Kochnev, Nikita S. Simonov, Alexey Y. Barkov","doi":"10.1016/j.tetlet.2025.155560","DOIUrl":"10.1016/j.tetlet.2025.155560","url":null,"abstract":"<div><div>In this work, we demonstrated a novel method for the synthesis of hemicurcuminods. The method is based on the Wittig olefination of aromatic, cinnamic and aliphatic aldehydes with 1-aryl-4-(triphenyl-λ<sup>5</sup>-phosphanylidene)butane-1,3-diones. This simple protocol has a broad aldehyde scope and great <em>E</em>-selectivity. The main advantage of this method is its ability to synthesize hemicurcuminoids containing acceptor groups and halogens in the styryl fragment with good yields. Hemicurcuminoids were obtained with a yield of up to 85 %. Moreover, this method can be easily scaled up for gram-scale synthesis of a wide scope of aromatic aldehydes.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"162 ","pages":"Article 155560"},"PeriodicalIF":1.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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