1-[(tert-Butyldimethylsilyl)oxy] alkenyl isocyanates 1a and 1b have been conveniently prepared from acetyl or propionyl chloride, silver cyanate and tert-butyldimethylsilyl triflate in the presence of triethylamine. They react with electron-deficient acetylenic dienophiles or with tosyl cyanide to give highly functionalised pyridines or derivatives of uracil or thymine in moderate yields. They also cycloadd with 1-(diethylamino)prop-1-yne, an electron-rich dienophile, to yield glutaconimides and pyridine derivatives.
{"title":"Synthesis and cycloadditions of 1-[(tert-butyldimethylsilyl)oxy]alkenyl isocyanates","authors":"C. D. Tollenaere, L. Ghosez","doi":"10.1002/CHIN.199835113","DOIUrl":"https://doi.org/10.1002/CHIN.199835113","url":null,"abstract":"1-[(tert-Butyldimethylsilyl)oxy] alkenyl isocyanates 1a and 1b have been conveniently prepared from acetyl or propionyl chloride, silver cyanate and tert-butyldimethylsilyl triflate in the presence of triethylamine. They react with electron-deficient acetylenic dienophiles or with tosyl cyanide to give highly functionalised pyridines or derivatives of uracil or thymine in moderate yields. They also cycloadd with 1-(diethylamino)prop-1-yne, an electron-rich dienophile, to yield glutaconimides and pyridine derivatives.","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80710839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1093/oso/9780199755905.003.0010
R. Hoffmann, V. Minkin, B. K. Carpenter
Nous commencons par retracer l'histoire personnelle de Guillaume d'Ockham, l'homme qui donna son nom au Rasoir d'Ockham. Ses formulations variees du principe de parcimonie sont presentees. Nous choisissons ensuite un mecanisme de reaction et decrivons une histoire personnelle sur la facon dont le Rasoir d'Ockham est engage dans l'etude d'un tel mecanisme. Une petite histoire des methodologies relatives au Rasoir d'Ockham, les principes de moindre action et de moindre mouvement sont ensuite abordes. L'ensemble est remis dans le contexte de l'acceptation par la communaute chimique (et scientifique) du principe comme etant valable d'un point de vue heuristique. Ce n'est pas le cas, a vrai dire, des attitudes philosophiques actuelles envers le Rasoir d'Ockham. Il s'ensuit un dialogue pour et contre. Nous presentons d'abord la discussion a l'interieur de la chimie, du principe fondamental qui sous-tend le Rasoir d'Ockham, a savoir que le monde est simple. Ensuite nous apportons des arguments qui prouvent, de maniere pragmatique, qu'a plus d'un egard, le Rasoir a son utilite sans avoir a postuler que le monde est simple. En poursuivant l'argumentation, nous nous interessons a la multiplicite et a la continuite des mecanismes de reaction concertes, et a la principale composante de l'analyse bayesienne (deux voies dans lesquelles le Rasoir d'Ockham est implique dans les statistiques modernes). Nous rendons, nous l'esperons, leurs merites aux dangers pour l'imagination chimique d'une adhesion rigide au point de vue du Rasoir d'Ockham, sans perdre de vue les profits qui resultent de l'utilisation de ce principe venerable.
{"title":"Ockham's Razor and Chemistry *","authors":"R. Hoffmann, V. Minkin, B. K. Carpenter","doi":"10.1093/oso/9780199755905.003.0010","DOIUrl":"https://doi.org/10.1093/oso/9780199755905.003.0010","url":null,"abstract":"Nous commencons par retracer l'histoire personnelle de Guillaume d'Ockham, l'homme qui donna son nom au Rasoir d'Ockham. Ses formulations variees du principe de parcimonie sont presentees. Nous choisissons ensuite un mecanisme de reaction et decrivons une histoire personnelle sur la facon dont le Rasoir d'Ockham est engage dans l'etude d'un tel mecanisme. Une petite histoire des methodologies relatives au Rasoir d'Ockham, les principes de moindre action et de moindre mouvement sont ensuite abordes. L'ensemble est remis dans le contexte de l'acceptation par la communaute chimique (et scientifique) du principe comme etant valable d'un point de vue heuristique. Ce n'est pas le cas, a vrai dire, des attitudes philosophiques actuelles envers le Rasoir d'Ockham. Il s'ensuit un dialogue pour et contre. Nous presentons d'abord la discussion a l'interieur de la chimie, du principe fondamental qui sous-tend le Rasoir d'Ockham, a savoir que le monde est simple. Ensuite nous apportons des arguments qui prouvent, de maniere pragmatique, qu'a plus d'un egard, le Rasoir a son utilite sans avoir a postuler que le monde est simple. En poursuivant l'argumentation, nous nous interessons a la multiplicite et a la continuite des mecanismes de reaction concertes, et a la principale composante de l'analyse bayesienne (deux voies dans lesquelles le Rasoir d'Ockham est implique dans les statistiques modernes). Nous rendons, nous l'esperons, leurs merites aux dangers pour l'imagination chimique d'une adhesion rigide au point de vue du Rasoir d'Ockham, sans perdre de vue les profits qui resultent de l'utilisation de ce principe venerable.","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78733348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-01-01DOI: 10.1142/9789812791405_0224
G. A. Olah, G. Rasul, H. Buchholz, Xing-ya Li, G. Prakash
Ab initio/IGLO (individual gauge for localized orbital) 29 Si NMR studies of trisubstituted silicenium and their related arenium ions have been carried out. Comparison of the obtained results with the reported experimental data indicate that to date no free long-lived trisubstituted silicenium cations have been observed in solution. The reported results in π-donor arene solvents clearly indicate the formation of silylated Wheland intermediates (arenium ions), whereas in previously discussed heteroatom n-donor solvents (such as ethers or nitriles) the related silylated onium (such as oxonium or nitrilium) ions are formed. At the same time due to the high electrophilicity of trivalent silicon and its affinity for oxygen, halogen, etc, counter ions, such as perchlorate or fluoroantimonates, are also unsuitable for the observation of long-lived trisubstituted silyl cations.
{"title":"Ab initio/IGLO 29Si NMR studies of trisubstituted silicenium and silylated arenium ions. Comparison with experimental data of claimed ions","authors":"G. A. Olah, G. Rasul, H. Buchholz, Xing-ya Li, G. Prakash","doi":"10.1142/9789812791405_0224","DOIUrl":"https://doi.org/10.1142/9789812791405_0224","url":null,"abstract":"Ab initio/IGLO (individual gauge for localized orbital) 29 Si NMR studies of trisubstituted silicenium and their related arenium ions have been carried out. Comparison of the obtained results with the reported experimental data indicate that to date no free long-lived trisubstituted silicenium cations have been observed in solution. The reported results in π-donor arene solvents clearly indicate the formation of silylated Wheland intermediates (arenium ions), whereas in previously discussed heteroatom n-donor solvents (such as ethers or nitriles) the related silylated onium (such as oxonium or nitrilium) ions are formed. At the same time due to the high electrophilicity of trivalent silicon and its affinity for oxygen, halogen, etc, counter ions, such as perchlorate or fluoroantimonates, are also unsuitable for the observation of long-lived trisubstituted silyl cations.","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82233577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Armin Dörr, D. Gudat, Dieter Hänssgen, H. Hens, E. Stahlhut
Multinuclear (1H, 15N, 29Si, 31P, 119Sn) NMR data of sterically crowded acyclic stannylphosphines tBu3SnPHY (Y = H, SnMe3, SntBu3, SiMe3; 1-3, 10), (tBu2RSn)2PH (R = Me, Cl; 4, 5), tBu3SnPY2 (Y = SnMe3, SiMe3; 6, 11), PH(SntBu2PHSntBu3)2 (7), SntBu2(PY2)2 (Y = H, SiMe3, PHSntBu3; 8, 9, 12), cyclic stannylphosphines (tBu2SnPY)n (n = 2, Y = H, C3H6Cl, tBu, SnMe3; 13-16; n = 3, Y = H; 18), (Me2SnPSntBu3)2 (17), and stannylamines tBu3SnNHY (Y = H, SnMe3, SntBu3; 19-21) were obtained by various 1D- and 2D-techniques. 31P- and 15N-shieldings may be explained qualitatively in terms of two counteracting influences, viz electronegativity differences and steric requirements of the substituents. In a similar manner, the trends in one-bond coupling 1KSnP and 1KSnM may be rationalized using a simple model based on the deformation of bond angles by sterically demanding substituents. The signs of long-range couplings 2KSnPH and 1KPSnCCH could be determined, which may be useful for future structural studies. Temperature-dependent effects in the spectra of 13, 18 allow conclusions about the conformational dynamics of the molecules.
{"title":"Multinuclear magnetic resonance study of sterically crowded stannylphosphines and stannylamines : stereochemical influences on chemical shielding and spin-spin couplings","authors":"Armin Dörr, D. Gudat, Dieter Hänssgen, H. Hens, E. Stahlhut","doi":"10.18419/OPUS-7985","DOIUrl":"https://doi.org/10.18419/OPUS-7985","url":null,"abstract":"Multinuclear (1H, 15N, 29Si, 31P, 119Sn) NMR data of sterically crowded acyclic stannylphosphines tBu3SnPHY (Y = H, SnMe3, SntBu3, SiMe3; 1-3, 10), (tBu2RSn)2PH (R = Me, Cl; 4, 5), tBu3SnPY2 (Y = SnMe3, SiMe3; 6, 11), PH(SntBu2PHSntBu3)2 (7), SntBu2(PY2)2 (Y = H, SiMe3, PHSntBu3; 8, 9, 12), cyclic stannylphosphines (tBu2SnPY)n (n = 2, Y = H, C3H6Cl, tBu, SnMe3; 13-16; n = 3, Y = H; 18), (Me2SnPSntBu3)2 (17), and stannylamines tBu3SnNHY (Y = H, SnMe3, SntBu3; 19-21) were obtained by various 1D- and 2D-techniques. 31P- and 15N-shieldings may be explained qualitatively in terms of two counteracting influences, viz electronegativity differences and steric requirements of the substituents. In a similar manner, the trends in one-bond coupling 1KSnP and 1KSnM may be rationalized using a simple model based on the deformation of bond angles by sterically demanding substituents. The signs of long-range couplings 2KSnPH and 1KPSnCCH could be determined, which may be useful for future structural studies. Temperature-dependent effects in the spectra of 13, 18 allow conclusions about the conformational dynamics of the molecules.","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88125645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.1007/978-1-4615-3000-8_34
H. Arzoumanian, José Sanchez, G. Strukul, R. Zennaro
{"title":"Dioxygen ligand transfer from platinum to molybdenum. Isolation of a highly reactive molybdenum (VI) oxoperoxo dimer","authors":"H. Arzoumanian, José Sanchez, G. Strukul, R. Zennaro","doi":"10.1007/978-1-4615-3000-8_34","DOIUrl":"https://doi.org/10.1007/978-1-4615-3000-8_34","url":null,"abstract":"","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88997612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
La methyl-4 heptanedione-2,6 est cyclisee en dimethyl-3,5 cyclohexene-2one. Le remplacement du groupe methyl-4 par un groupe isopropyl ou t-butyl conduit a une baisse importante de l'enantioselectivite
{"title":"Enantioselective cyclizations of acyclic 1,5-diketones","authors":"C. Agami*, N. Platzer, H. Sevestre","doi":"10.1002/CHIN.198739126","DOIUrl":"https://doi.org/10.1002/CHIN.198739126","url":null,"abstract":"La methyl-4 heptanedione-2,6 est cyclisee en dimethyl-3,5 cyclohexene-2one. Le remplacement du groupe methyl-4 par un groupe isopropyl ou t-butyl conduit a une baisse importante de l'enantioselectivite","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1987-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91468449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Trifluoropyruvic acid hydrate in heterocyclic synthesis: synthesis of trifluoromethylated five, six and seven membered heterocycles with two or more heteroatoms","authors":"M. Mustafa, A. Takaoka, N. Ishikawa","doi":"10.1002/CHIN.198726070","DOIUrl":"https://doi.org/10.1002/CHIN.198726070","url":null,"abstract":"","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1987-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91459861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synthese par fluoration de methylcyclooctane, cyclodecane, cyclododecane, cyclotetradecane, dipropyl-4,4 heptane, diethyl-3,3 pentane
合成对氟化去甲基环辛烷、环癸烷、环十二烷、环十四烷、二丙基4,4庚烷、二乙基3,3戊烷
{"title":"Synthesis of new high molecular weight cyclic fluorocarbons and highly branched fluorocarbons such as perfluoro-3,3-diethylpentane","authors":"Hsu-Nan Huang, R. Lagow","doi":"10.1002/CHIN.198726099","DOIUrl":"https://doi.org/10.1002/CHIN.198726099","url":null,"abstract":"Synthese par fluoration de methylcyclooctane, cyclodecane, cyclododecane, cyclotetradecane, dipropyl-4,4 heptane, diethyl-3,3 pentane","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1987-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80411686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluorhydratation de liaisons acetyleniques activees par des groupes nitrile, ester, cetone ou aldehyde. Obtention des isomeres cis- ou -trans des derives fluoroethyleniques correspondants
由丁腈、酯、酮或醛基团活化的乙炔键的氟化。生产相应的氟乙基衍生物的顺式或反式异构体
{"title":"Tetrabutylammonium and polymer-supported dihydrogentrifluoride: new reagents for the hydrofluorination of activated acetylenic bonds","authors":"J. Cousseau, P. Albert","doi":"10.1002/chin.198725096","DOIUrl":"https://doi.org/10.1002/chin.198725096","url":null,"abstract":"Fluorhydratation de liaisons acetyleniques activees par des groupes nitrile, ester, cetone ou aldehyde. Obtention des isomeres cis- ou -trans des derives fluoroethyleniques correspondants","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1987-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86436326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synthese de R-2 benzooxazoles par action de R-COOH sur l'amino-2 phenol en presence de PPSE
在PPSE存在下，R-COOH对氨基-2酚的作用合成R-2苯并恶唑
{"title":"Reagents and synthetic methods. XXVII: Improved synthesis of 2-substituted benzoxazoles induced by trimethylsilyl polyphosphate (PPSE)","authors":"J. Aizpurua, C. Palomo","doi":"10.1002/chin.198436190","DOIUrl":"https://doi.org/10.1002/chin.198436190","url":null,"abstract":"Synthese de R-2 benzooxazoles par action de R-COOH sur l'amino-2 phenol en presence de PPSE","PeriodicalId":9281,"journal":{"name":"Bulletin de la Société Chimique de France","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1984-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73817458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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