Bromine-Catalyzed Aziridination of Olefins. A Rare Example of Atom-Transfer Redox Catalysis by a Main Group Element

Jeong, Jae Uk; Tao, Beata; Sagasser, I.; Henniges, and Hans; Sharpless, K. Barry

doi:10.1021/ja981419g

Cited by 311 publications

(197 citation statements)

References 22 publications

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“…To the best of our knowledge, acetonitrile participation has not been otherwise reported in the aziridination reaction under the Sharpless conditions [26]. However, we believe that the involvement of acetonitrile in the reaction of compound 1 under the same conditions can be readily understood in terms of our initial hypothesis.…”

Section: Methodsmentioning

confidence: 62%

“…We also note that while the Sharpless aziridination is reported to take 12 hours at room temperature [26,27], the reaction of compound 1 went to completion within 40 minutes at 0 °C. The reaction gave similar results whether run at room temperature or at 0 °C.…”

Section: Methodsmentioning

confidence: 68%

“…However, we believe that the involvement of acetonitrile in the reaction of compound 1 under the same conditions can be readily understood in terms of our initial hypothesis. Chloramine-T is a strong nucleophile [26,30], so it is not surprising that it attacks the bromonium ion preferentially in the case of ordinary bromonium ion intermediates. However, if as we expected, the cyclopropyl bromonium ion is delocalized through both three-membered rings, and both rings are opened at the same time, then as we have observed with compounds 2 and 5, the reactivity would be expected to be much higher than an ordinary bromonium ion.…”

Section: Methodsmentioning

confidence: 99%

“…One of the better general methods for accomplishing the aziridination of alkenes is Sharpless' reaction, in which a source of Br + (phenyltrimethylammonium tribromide, PTAB) catalyses a process using chloramine-T (TsNNaCl) as the nitrogen source [26]. The reaction is believed to proceed through a bromonium ion [26], and has been successfully used by Chandrasekaran for the preparation of tosyl aziridine 6 of (+)-3-carene 3 (Scheme 6) [27]. The intermediate bromonium ion in that case was not adjacent to the cyclopropane ring, and the cyclopropane ring remained unaffected [27].…”

Section: -Carene and Nitrogen Nucleophilesmentioning

confidence: 99%

“…We performed the reaction of compound 1 according to the procedure of Sharpless [26,27]. The major product 13 was a solid.…”

Section: -Carene and Nitrogen Nucleophilesmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 68%

Section: Methodsmentioning

confidence: 99%