.alpha.-Imino and .alpha.-Oximino Carbocations. A Comparison with .alpha.-Carbonyl and .alpha.-Thiocarbonyl Carbocations

Creary, Xavier; Wang, You-Xiong; Jiang, Ziqi

doi:10.1021/ja00116a010

Cited by 27 publications

(27 citation statements)

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“…132-133°C. 1 Preparation of oxime 11. A solution of 403 mg of ethyl vinyl ether (4.22 mmol) in 5 ml of dry tetrahydrofuran was cooled to À78°C and 1.7 ml of 1.7 M tertbutyllithium (2.89 mmol) in pentane was added dropwise.…”

Section: Methodsmentioning

confidence: 99%

“…9-Acetyl-9-hydroxyfluorene (136 mg; 27% yield from fluorenone) eluted with 10% diethyl ether in hexanes. 1 Preparation of oxime 14. A solution of 0.550 g of silylated cyanohydrin 12 15 (1.97 mmol) in 5 ml of dry diethyl ether was stirred under nitrogen and 3.0 ml of 1.0 M isopropylmagnesium bromide in diethyl ether was added dropwise.…”

Section: Methodsmentioning

confidence: 99%

“…The residue was chromatographed on 20 g of silica gel and eluted with 5% diethyl ether in hexanes to give 0.232 g (55% yield) of the a-hydroxyketone 13. 1 Kinetic studies. Rates of solvolyses of chlorides 15-18 in methanol (2.5 Â 10 À4 M in 2,6-lutidine) were monitored by UV spectrophotometry at 245 nm using the previously described method.…”

Section: Methodsmentioning

confidence: 99%

“…1,2 This group is inductively electron withdrawing as reflected by a s I value of 0.14. However, our studies have shown that the oxime group can be an effective cation stabilizing group and this is attributed to charge delocalization utilizing the oxime group as represented by 1a and 1b.…”

Section: Introductionmentioning

confidence: 99%

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Effect of oxime substituents on 9-fluorenyl carbocations

Creary¹,

Wolf²

2000

J. Phys. Org. Chem.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of oxime substituents on 9-fluorenyl carbocations

Creary¹,

Wolf²

2000

J. Phys. Org. Chem.

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“…After formation of the nitrilium ion, a 1,2 hydride shift occurs, producing an α-imino cation, which is stabilized by delocalization [32]. …”

Section: Scheme 11mentioning

confidence: 99%

Reactions of the halonium ions of carenes and pinenes: An experimental and theoretical study

et al. 2015

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The reactions of vinylcyclopropane (+)-2-carene (1) and vinylcyclobutanes (-)-β-pinene (7), (-)-α-pinene (11), and (-)-nopol (12) with electrophilic halogens in the presence of oxygen and nitrogen nucleophiles in various solvents have been investigated. The halonium ion intermediates that were presumably formed were very reactive and led to opening of the conjugated cyclopropane or cyclobutane. Reactions of chloramine-T trihydrate with compound 1 in acetonitrile gave amidine 13 and diazepine 14. Reactions of chloramine-T trihydrate with pinenes in methylene chloride gave allylic tosylamines 22, 16B and 24. Mechanisms to explain the observations are proposed and supported by ab initio and Density Functional Theory calculations on the carenes and pinenes in this report and their bromonium ion intermediates. For comparisons, the relative extent of conjugation with the bromonium ion moiety of these, as well as select cyclohexene and cyclohexadiene systems and their corresponding bromonium ions, were optimized at the B3LYP/cc-pVDZ level of theory, and then these geometries were analyzed using the absolute hardness index at the HartreeFock/aug-cc-pVDZ and B3LYP/aug-cc-pVDZ levels of theory. Additionally, Natural Population Analysis charges were calculated for these systems using Møller-Plessett Second-Order Perturbation Theory electron densities and the aug-cc-pVDZ basis set. Combining the results of these theoretical methods with analysis of structural details of their optimized geometries gives much electronic structure insight into the extent of conjugation of bromonium ions of the carenes and pinenes reported here, and places them in relative context of more traditional conjugated and non-conjugated bromonium ion systems. In particular, bromonium ions of compounds 1, 7, and 11 display structural distortions, charge delocalizations and hardness values comparable with those of traditional conjugated cyclohexadienes, with possible reasons for subtle differences presented.

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