Formation, properties, and reactions of the 1,2:3,4:5,6-tris(bicyclo[2.2.2]octeno)tropylium ion

Komatsu, Kôichi; Akamatsu, Hidekazu; Aonuma, Shuji; Jinbu, Yasuhisa; Maekawa, Nobuhiro; Takeuchi, Ken′ichi

doi:10.1016/s0040-4020(01)96150-2

Cited by 32 publications

(11 citation statements)

References 21 publications

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“…NMR characterization of cation 210 showed 453 significant upfield shifts of the protons of the phenyl rings and the carbons of the cyclopropenylium ring, whereas downfield shifts was noted of most of the naphthalene ring carbons when compared with cation 211. 461 Similar cations with other fused rings have been reported recently. This information gives strong evidence that the diphenylcyclopropenylium units in dication 210 have essentially face-to-face conformation.…”

Section: Trivalent Carbocationssupporting

confidence: 79%

Carbocations in Superacid Systems

Oláh¹,

Prakash²,

Molnár³

et al. 2008

Superacid Chemistry

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Section: Trivalent Carbocationssupporting

confidence: 79%

Carbocations in Superacid Systems

Oláh¹,

Prakash²,

Molnár³

et al. 2008

Superacid Chemistry

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“…In spite of the severe steric hindrance by three BCO units, the central ring of benzene 20 was enlarged by a CuBr‐catalyzed reaction with a large excess of diazomethane to give tris‐BCO‐annelated cycloheptatriene 24 in 30% yield (73% yield based on consumed 20 ). Conventional hydride abstraction from 24 with the triphenylmethyl cation afforded the desired tropylium ion 19 in 91% yield (Scheme ) . To our great delight, the p K R + value for this new cation 19 was determined to be 13.0, which is the highest value ever reported for a tropylium ion made only of hydrocarbons .…”

Section: Stabilization Of the Tropylium Ion By σ–π Conjugationmentioning

confidence: 89%

“…Conventional hydride abstraction from 24 with the triphenylmethyl cation afforded the desired tropylium ion 19 in 91% yield (Scheme ) . To our great delight, the p K R + value for this new cation 19 was determined to be 13.0, which is the highest value ever reported for a tropylium ion made only of hydrocarbons . This is attributed to the inductive effect plus σ–π conjugation of the tropylium 2p orbitals with six σ bonds, which are rigidly fixed in a position nearly parallel to the vacant 2p orbitals.…”

Section: Stabilization Of the Tropylium Ion By σ–π Conjugationmentioning

confidence: 99%

Professor Tetsuo Nozoe and My Tropylium Ion Chemistry

Komatsu

2014

The Chemical Record

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Needless to say, the discovery of hinokitiol with its "unconventional" aromaticity by Professor Tetsuo Nozoe is one of the most important achievements in organic chemistry in the last century. The essence of this "non-benzenoid" aromaticity in hinokitiol is of course that of tropolone, and it is further related to the aromaticity of tropone and the tropylium ion, i.e., the cycloheptatrienyl cation. In this account, details of the study conducted by the author's group, particularly on the synthesis and properties of tropylium ion derivatives with various unique structures pursuing the ultimately high carbocation stability, are described.

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“…22 However, 14 + does react with organolithium reagents at the 7-position and affords the tropylium ion derivatives 15 + , 20 16 + , 23 17 2+ , 23 18 2+ , 23 and 19 2+ (Figure 7) 24 by appropriate ionization methods. The pK R + and reduction potential data of these mono-and dications are given in Table 4.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Properties of Cationic π-Conjugated Systems Stabilized by Bicyclo[2.2.2]octene Units

Komatsu¹,

Nishinaga²

2005

Synlett

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The purpose of this Account is to present the results of our systematic study on the synthesis of a series of cyclic p-conjugated systems with the monocyclic six-membered to eight-membered rings as well as polycyclic aromatic compounds, which are fully surrounded by rigid bicyclic s-frameworks. This structural modification is characteristic in causing elevation of the HOMO levels of neutral p-systems and remarkably stabilizing the corresponding cationic systems by both thermodynamic and kinetic effects. In order to minimize the possible steric strain in p-systems, the relatively strain-free bicyclic system, i.e., bicyclo[2.2.2]octene, was chosen for the structural modification of all the cyclic p-systems, and the successful generation of the cationic species such as radical cation, closed-shell mono-and dications, which are so stable to allow even the X-ray structural analysis, is demonstrated.

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Formation, properties, and reactions of the 1,2:3,4:5,6-tris(bicyclo[2.2.2]octeno)tropylium ion

Cited by 32 publications

References 21 publications

Carbocations in Superacid Systems

Carbocations in Superacid Systems

Professor Tetsuo Nozoe and My Tropylium Ion Chemistry

Synthesis and Properties of Cationic π-Conjugated Systems Stabilized by Bicyclo[2.2.2]octene Units

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