Synthesis, stability, and crystal structure of an azulenium cation containing an adamantyl group

Mitsunori Oda; Nobue Nakajima; Nguyen Chung Thanh; Kazuhiro Kitahara; Ryuta Miyatake; Shigeyasu Kuroda

doi:10.1002/ejoc.200800700

Synthesis, stability, and crystal structure of an azulenium cation containing an adamantyl group

Mitsunori Oda^*, Nobue Nakajima, Nguyen Chung Thanh, Kazuhiro Kitahara, Ryuta Miyatake, Shigeyasu Kuroda

^*Corresponding author for this work

Center for Environmental Conservation and Research Safety

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

Starting from the trimethylsilyl enol ether of 1-acetyl-1,3,5- cycloheptatriene, the title 1H-azulenium cation was synthesized by a five-step sequence that involved a Noyori-Mukaiyama aldol reaction, a Nazarov cyclization, a Shapiro reaction, and a hydride abstraction. The Nazarov reaction of the aldol-type adduct resulted in the formation of an unusual double-bond position isomer, which has never been obtained in similar reactions forming tetrahydroazulenones. The pK_R⁺ value of the title cation was found to be 9.8, which is less than that expected by inductive stabilization from the number of carbons at the 1-position. The X-ray crystal structure of the title cation (ClO₄^- salt) reveals CH-O interactions and deformation of the azulenyl ion part.

Original language	English
Pages (from-to)	5301-5307
Number of pages	7
Journal	European Journal of Organic Chemistry
Issue number	31
DOIs	https://doi.org/10.1002/ejoc.200800700
State	Published - 2008/11

Keywords

Carbocations
Nazarov cyclizations
Spiro compounds

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry

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10.1002/ejoc.200800700

Cite this

@article{784eb8e22595476c9b0064f235e865ab,

title = "Synthesis, stability, and crystal structure of an azulenium cation containing an adamantyl group",

abstract = "Starting from the trimethylsilyl enol ether of 1-acetyl-1,3,5- cycloheptatriene, the title 1H-azulenium cation was synthesized by a five-step sequence that involved a Noyori-Mukaiyama aldol reaction, a Nazarov cyclization, a Shapiro reaction, and a hydride abstraction. The Nazarov reaction of the aldol-type adduct resulted in the formation of an unusual double-bond position isomer, which has never been obtained in similar reactions forming tetrahydroazulenones. The pKR+ value of the title cation was found to be 9.8, which is less than that expected by inductive stabilization from the number of carbons at the 1-position. The X-ray crystal structure of the title cation (ClO4- salt) reveals CH-O interactions and deformation of the azulenyl ion part.",

keywords = "Carbocations, Nazarov cyclizations, Spiro compounds",

author = "Mitsunori Oda and Nobue Nakajima and Thanh, {Nguyen Chung} and Kazuhiro Kitahara and Ryuta Miyatake and Shigeyasu Kuroda",

year = "2008",

month = nov,

doi = "10.1002/ejoc.200800700",

language = "英語",

pages = "5301--5307",

journal = "European Journal of Organic Chemistry",

issn = "1434-193X",

publisher = "Wiley-VCH Verlag",

number = "31",

}

TY - JOUR

T1 - Synthesis, stability, and crystal structure of an azulenium cation containing an adamantyl group

AU - Oda, Mitsunori

AU - Nakajima, Nobue

AU - Thanh, Nguyen Chung

AU - Kitahara, Kazuhiro

AU - Miyatake, Ryuta

AU - Kuroda, Shigeyasu

PY - 2008/11

Y1 - 2008/11

N2 - Starting from the trimethylsilyl enol ether of 1-acetyl-1,3,5- cycloheptatriene, the title 1H-azulenium cation was synthesized by a five-step sequence that involved a Noyori-Mukaiyama aldol reaction, a Nazarov cyclization, a Shapiro reaction, and a hydride abstraction. The Nazarov reaction of the aldol-type adduct resulted in the formation of an unusual double-bond position isomer, which has never been obtained in similar reactions forming tetrahydroazulenones. The pKR+ value of the title cation was found to be 9.8, which is less than that expected by inductive stabilization from the number of carbons at the 1-position. The X-ray crystal structure of the title cation (ClO4- salt) reveals CH-O interactions and deformation of the azulenyl ion part.

AB - Starting from the trimethylsilyl enol ether of 1-acetyl-1,3,5- cycloheptatriene, the title 1H-azulenium cation was synthesized by a five-step sequence that involved a Noyori-Mukaiyama aldol reaction, a Nazarov cyclization, a Shapiro reaction, and a hydride abstraction. The Nazarov reaction of the aldol-type adduct resulted in the formation of an unusual double-bond position isomer, which has never been obtained in similar reactions forming tetrahydroazulenones. The pKR+ value of the title cation was found to be 9.8, which is less than that expected by inductive stabilization from the number of carbons at the 1-position. The X-ray crystal structure of the title cation (ClO4- salt) reveals CH-O interactions and deformation of the azulenyl ion part.

KW - Carbocations

KW - Nazarov cyclizations

KW - Spiro compounds

UR - http://www.scopus.com/inward/record.url?scp=55049114235&partnerID=8YFLogxK

U2 - 10.1002/ejoc.200800700

DO - 10.1002/ejoc.200800700

M3 - 学術論文

AN - SCOPUS:55049114235

SN - 1434-193X

SP - 5301

EP - 5307

JO - European Journal of Organic Chemistry

JF - European Journal of Organic Chemistry

IS - 31

ER -

Synthesis, stability, and crystal structure of an azulenium cation containing an adamantyl group

Abstract

Keywords

ASJC Scopus subject areas

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