13C-19F couplings and 19F NMR shifts of cycloalkyl, bicycloalkyl and steroid monofluoro compounds

Schneider, Hans‐Jörg; Gschwendtner, W.; Heiske, D.; Hoppen, Volker; Thomas, F.

doi:10.1016/0040-4020(77)84058-1

Cited by 31 publications

(18 citation statements)

References 40 publications

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“…The magnitude of the measured 1 J C,F of C1-F in 1 is similar to those reported for cycloalkyl compounds by Schneider et al 36 The relative sign of this 1 J C,F was determined by our method to be negative (calc. 2, Table 1).…”

Section: Resultssupporting

confidence: 89%

“…In total, 17 and 18 RDCs were collected when the compound was oriented by bicelles or phage, respectively. 27 The signs of 1 36,38 showed that the sign of the geminal coupling 2 J C,F is generally positive and that the magnitude does not show a significant dependence on stereochemistry or on the electronegativity of additional substituents. The two observed 2 J C,F of the compound are C24.4 (C2-F) and C23.6 (C5-F) Hz, respectively, and comparable to those reported in various compounds previously.…”

Section: Resultsmentioning

confidence: 97%

“…The two observed 2 J C,F of the compound are C24.4 (C2-F) and C23.6 (C5-F) Hz, respectively, and comparable to those reported in various compounds previously. 36,38 When the sign of the 2 J C,F was determined using the order matrix calculation, the signs of the corresponding RDCs of C2-F and C5-F were switched simultaneously, which resulted in a sufficient r.m.s.d. difference (1.33 Hz), strongly suggesting that the sign of 2 J C,F is positive.…”

Section: Resultsmentioning

confidence: 99%

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The absolute sign of J coupling constants determined using the order matrix calculation

Yan

Kline

et al. 2004

Magnetic Reson in Chemistry

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A novel methodology using the order matrix calculation to determine the absolute sign of spin-spin couplings based on the structure of organic compounds is presented. The sign of the residual dipolar coupling (RDC) depends on the sign of corresponding scalar spin-spin coupling constant and the sign of the RDC has a dramatic influence on the order matrix calculation. Therefore, the sign of the spin-spin coupling constant can be obtained by an order matrix calculation through the corresponding RDC. Six types of spin-spin coupling constants, including 2J(H,H), 1J(C,F), 2J(C,F), 3J(C,F), 2J(F,H) and 3J(F,H), were obtained simultaneously. Except for 3J(C,F) where the measured RDCs have very small magnitudes, the signs were determined unambiguously.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

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The absolute sign of J coupling constants determined using the order matrix calculation

Yan

Kline

et al. 2004

Magnetic Reson in Chemistry

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“…According to ref. 4, the large coupling constant 3JC5e-~ = 13.7 Hz observed for the doublet at 28.62 pprn is indicative of an angle near 160-180" and therefore identifies C5 of the C, form (represented by C5e) while the C5a carbon is found at 26.05 pprn (doublet with 3JC5a-F = 4.3 Hz).…”

Section: Spectral Analysis and Stable Conformations Of Compounds 4-14mentioning

confidence: 99%

NMR study of π–σ* stereoelectronic interactions in 3-substituted benzocycloheptene derivatives

Aubin¹,

St‐Jacques²

1990

Can. J. Chem.

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IY. AUBIN and M. ST-JACQUES. Can. J. Chem. 68, 543 (1990). Dynamic NMR methods are used to study 3-substituted benzocycloheptene derivatives, useful models for investigating the conformational effect of the stereoelectronic T-u* orbital interaction. The 11 compounds studied are divided in two subgroups, the first one containing mainly halogenated derivatives (F, C1, Br, and 0CH3) and the second consisting of oxy derivatives (OCH3, 0CH2CH3, 0CH=CH2, OAc, p-OPh-R, where R = H, 0CH3, and NO2). The results for the first series show the presence of two chair conformations (C, and C,) characterized by a decreasing C, population with increasing electronegativity of the substituent. This trend suggests the presence of a dominant T-cr* interaction for Cl and Br stabilizing the C, form. The larger C, population observed for F suggests that a strong attractive interaction with the aromatic peri hydrogen is present in this compound. Finally, in the oxy-substituent series, the populations trend does not correspond to that predicted from the T-o* orbital interaction, but the individual population perturbations appear to be caused primarily by electrostatic interactions involving the nonsymmetrical polar substituents.Key words: low temperature NMR, conformational analysis, seven-membered rings, orbital interactions, benzocycloheptene derivatives.Y. AUBIN et M. ST-JACQUES. Can. J. Chem. 68, 543 (1990). On a utilisC des mCthodes de RMN dynamique pour Ctudier des benzocycloheptenes substituCs en position 3 qui sont de bons modeles pour Cvaluer l'effet conformationnel de l'interaction stCrCoClectronique de l'orbitale T-o*. Les 1 1 composts CtudiCs ont Ct C divisCs en deux sous-groupes : le premier comprend principalement des dCrivCs halogCnCs (F, C1, Br et 0CH3) alors que le second est form6 de dtrivts oxygCnCs (OCH3, 0CH2CH3, 0CH=CH2, OAc et p-OPh-R dans lequel R = H, 0CH3 et NO2). Les rksultats obtenus avec la premiere serie de composCs dCmontrent que deux conformations chaises (C, et C,) sont prCsentes et que la population de la conformation C, diminue avec une augmentation de 1'ClectronCgativitC du substituant. Cette tendance suggere que, pour les substituants C1 et Br, il existe une interaction T-cr* dominante qui stabilise la forme C,. La prisence d'une population plus Clevte de C, avec le F suggkre que, dans ce composC, l'hydrogene aromatique en pkri exerce une forte interaction attractive. Enfin, dans les composCs oxygCnCs, les variations des populations ne correspondent pas celles que l'on pourrait prCvoir en se basant sur l'interaction de l'orbitale T-IT* ; toutefois, les perturbations dans les populations individuelles semblent reflCter principalement des interactions Clectrostatiques impliquant les substituants polaires qui ne sont pas symCtriques. I Mots cle's : RMN i basse temperature, analyse conformationnelle, cycles 2 sept chainons, interactions orbitales, dCrivCs de benzocyclohept~ne.

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“…After stirring for 18 h, the appropriate amount of NMR internal standard was added (m-fluorotoluene) a sample analyzed by NMR. 19 F NMR (CDCl 3 , CFCl 3 ): d À167.7 (dm, 1F, 2 J FH = 50 Hz, J FH = 7 Hz, CHF) [14].…”

Section: -Phenylfluoroethane (6)mentioning

confidence: 99%

1,1,3,3,3-Pentafluoropropene secondary amine adducts new selective fluorinating agents

Koroniak

Walkowiak

Grys

et al. 2006

Journal of Fluorine Chemistry

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13C-19F couplings and 19F NMR shifts of cycloalkyl, bicycloalkyl and steroid monofluoro compounds

Cited by 31 publications

References 40 publications

The absolute sign of J coupling constants determined using the order matrix calculation

The absolute sign of J coupling constants determined using the order matrix calculation

NMR study of π–σ* stereoelectronic interactions in 3-substituted benzocycloheptene derivatives

1,1,3,3,3-Pentafluoropropene secondary amine adducts new selective fluorinating agents

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