bicyclic strained allenes: incorporation of an allene unit into alpha-pinene and ...

239 Pages·2004·4.43 MB·English

BICYCLIC STRAINED ALLENES:
INCORPORATION OF AN ALLENE UNIT INTO
ALPHA-PINENE AND BENZONORBORNADIENE
A THESIS SUBMITTED TO
THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES
OF
MIDDLE EAST TECHNICAL UNIVERSITY
BY
AKIN AZÝZOÐLU
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE
OF
DOCTOR OF PHILOSOPHY
IN
CHEMISTRY
JUNE 2004
Approval of the Graduate School of Natural and Applied Sciences
Prof. Dr. Canan Özgen
Director
I certify that this thesis satisfies all the requirements as a thesis for the degree of
Doctor of Philosophy.
Prof. Dr. Hüseyin Ýþçi
Head of Department
This is to certify that we have read this thesis and that in our opinion it is fully
adequate, in scope and quality, as a thesis for the degree of Doctor of Philosophy.
Prof. Dr. Metin Balcý
Supervisor
Examining Committee Members
Prof. Dr. Ayhan S. Demir (METU, CHEM)
Prof. Dr. Metin Balcý (METU, CHEM)
Prof. Dr. Cihangir Tanyeli (METU, CHEM)
Prof. Dr. Canan Ünaleroðlu (HACETTEPE UNIV., CHEM)
Prof. Dr. Basri Atasoy (GAZÝ UNIV.,CHEM EDUC)
I hereby declare that all information in this document has been obtained and
presented in accordance with academic rules and ethical conduct. I also declare that,
as required by these rules and conduct, I have fully cited and referenced all material
and results that are not original to this work.
Name, Last name : AKIN AZÝZOÐLU
Signature :
ABSTRACT
BICYCLIC STRAINED ALLENES:
INCORPORATION OF AN ALLENE UNIT INTO
ALPHA PINENE
AND
BENZONORBORNADIENE
Azizoðlu, Akýn
Ph.D., Department of Chemistry
Supervisor: Prof. Dr. Metin Balcý
June 2004, 221 pages
The first part of study describes an investigation aimed at the incorporation of
an allene unit into a natural compound, being alpha-pinene, by using Doering-
Moore-Skatteboel method. DFT computations show that both allene product and
insertion product can be isolated if the reaction of methyllithium with 3,3-dibromo-
2,7,7-trimethyl-tricyclo[4.1.1.02,4]octane is carried out at either low or high
temperatures. One insertion product resulting from the intramolecular C-H insertion
at the bridge and three allene dimers were isolated when this reaction was carried out
at room temperature.
iv
In the second part of study, exo- and endo-cyclopropylidene incorporated into
benzonorbornadiene were investigated by using theoretical and experimental
methods. Theoretical calculations show that the endo-carbene would be stable and
undergo some kind of insertion and addition reactions. On the contrary, the exo-
carbene is not stable and isomerizes to the corresponding allene structure during the
optimization process.
For this purpose, the reaction of dibromocarbene and dichlorocarbene with
7-methoxybenzonorbornadiene was achieved to afford gem-dibromocyclopropane
and gem-dichlorocyclopropane adducts, respectively. However, they suffer
stereoelectronically-controlled ring opening under the reaction conditions to give the
ring-expanded allylic dihalides, respectively.
On the other hand, gem-bromofluorocyclopropane, obtained by the treatment
of 7-methoxybenzonorbornadiene with bromofluorocarbene, provided one of the four
possible [2+4] allene adducts upon treatment with MeLi in furan. The exact structure
of the adduct has been elucidated on the basis of NMR spectral data. This result
confirms the formation of the bicyclic allene as an reactive intermediate. No products
were isolated derived from the endo-carbene.
Keywords: Allene, Bicyclic Allene, Cyclodimerization, Carbene, Insertion, Alpha-
pinene, Doering-Moore-Skattebol Method, Benzonorbornadiene, Solvolysis,
Bromination, Elimination, DFT Method, Theoretical Calculations.
v
ÖZ
BÝSÝKLÝK GERÝLÝMLÝ ALLENLER:
ALLEN BÝRÝMÝNÝN ALFA-PÝNEN
VE
BENZONORBORNADÝEN
MOLEKÜLLERÝNE DAHÝL EDÝLMESÝ
Azizoðlu, Akýn
Doktora, Kimya Bölümü
Tez Yöneticisi: Prof. Dr. Metin Balcý
Haziran 2004, 221 sayfa
Çalýþmamýzýn birinci bölümünde, Doering-Moore-Skattebol yöntemini
kullanarak, doðal bir bileþik olan alfa-pinen içerisinde allen biriminin oluþturulmasý
amaçlanmýþtýr. DFT hesaplarýna göre, eðer 3,3-dibrom-2,7,7-trimetil-
trisiklo[4.1.1.02,4]oktan ile metillityum reaksiyona sokulursa, allen ve insersiyon
ürünleri izole edilecektir. Bu reaksiyon oda sýcaklýðýnda yapýldýðýnda, köprü
konumunda molekül içi C-H insersiyon reaksiyonu sonucu oluºan ürün ile üç tane
allen dimeri elde edilmiºtir.
vi
Çalýþmamýzýn ikinci bölümünde ise, benzonorbornadien molekülünde
oluºturulan exo- ve endo-siklopropilidenler, teorik ve deneysel olarak incelenmiºtir.
Teorik hesaplar sonucunda, endo-karbenin kararlý olacaðý ve bazý insersiyon ve
katýlma reaksiyonlarýný verebileceði bulunmuþtur. Bununla birlikte, exo-karbenin
kararlý olmadýðý ve optimizasyon iþlemi esnasýnda ilgili allen yapýsýna dönüþtüðü
bulunmuºtur.
Bu amaçla, 7-methoksibenzonorbornadien ile dibromkarben ve
diklorkarbenin reaksiyonlarý, gem-dibromsiklopropiliden ve gem-
diklorsiklopropilideni sentezlemek amacýyla gerçekleþtirilmiþtir. Fakat, reaksiyon
esnasýnda bu bileþikler steroelektronik kontrollü olarak açýlmýþ ve halka geniþleyerek
alilik dihalojenleri vermiºtir.
Bununla birlikte, 7-methoksibenzonorbornadien ile bromflorkarbenin
reaksiyonu gem-bromflorsiklopropilideni vermiºtir. Elde edilen bileºik metillityum
ile furan içerisinde reaksiyona sokuldu. Oluþan allen ve ortamdaki furanýn [2+4]-
siklokatýlma reaksiyonun sonucu olan tek bir ürün elde edildi. Bu sonuç, bisiklik
allenin reaktif ara ürün olarak oluþtuðunu göstermektedir. Endo-karbenden oluºan
hiç bir ürün izole edilememiºtir.
Anahtar Kelimeler: Allen, Bisiklik Allen, Siklodimerleºme, Karben, Insersiyon,
Alfa-pinen, Doering-Moore-Skattebol metodu, Benzonorbornadien, Solvoliz,
Brominasyon, Eliminasyon, DFT metodu, Teorik hesaplar.
vii
To my wife Nursen and my daughter Ece
viii
ACKNOWLEDGEMENTS
I would like to express my sincere thanks to my supervisor Prof. Dr. Metin
Balcý for his continuous guidance, endless support, patience and encouragement
throught this work.
My extensive thanks are offered to Assist. Prof. Dr. Recep Özen for his
endless help, comments and close interest as a friend.
Thanks also extended to Fatih Algý for his unique friendship, help and
comments.
I wish to express my thanks to NMR specialist Fatoº Polat Doðanel for the
perfect NMR spectra.
I would like to thank to Prof. Dr. Ayhan S. Demir who let us to get GC/MS
spectra and his skillful assistant Ömer Reis for taking these spectra.
I also give my thanks to the members of our research group; SYNTHOR.
Finally, my special appreciation and great gratitude is devoted to my wife
Nursen Azizoðlu for her endless love, patience, moral support and encouregement in
every moment of our life.
ix
TABLE OF CONTENTS
ABSTRACT…………………………………………………………………. iv
ÖZ……………………………………………………………………………. vi
ACKNOWLEDGEMENTS………………………………………………… ix
TABLE OF CONTENTS…………………………………………………… x
LIST OF TABLES………………………………………………………….. xiii
LIST OF FIGURES………………………………………………………… xv
LIST OF ABBREVIATIONS……………………………………………… xvii
CHAPTER
1. INTRODUCTION……………………………………………………….. 1
1.1. Strained Cyclic Allenes………………………………………………. 3
1.1.1. Cyclonona-1,2-diene and Its Derivatives……………………… 5
1.1.2. Cycloocta-1,2-diene and Its Derivatives……………………….. 8
1.1.3. Cyclohepta-1,2-diene and Its Derivatives……………………… 10
1.1.4. Cyclohexa-1,2-diene and Its Derivatives………………………. 16
1.1.5. Cyclopenta-1,2-diene and Its Derivatives……………………… 41
1.2. Strained Bicyclic Allenes……………………………….……………. 44
1.3. Aims of The Study……………………………….…………………… 56
2. RESULTS AND DISCUSSION…………………………………………..
2.1. The reaction path for the synthesis of 2,6,6-trimethyl-bicyclo[3.1.1]
hepta-2,3-diene (371)……………………………………………………… 57
2.1.1. Bromination of 1R-(-)-a -Pinene……………………………… 57
2.2. The reaction path for the synthesis of 2,7,7-trimethyl-
bicyclo[4.1.1]octa-2,3-diene (372)………………………………………… 60
2.2.1. Reaction of dibromocarbene with 1R-(-)-a -pinene…………… 60
2.2.2. The heat stability of 3,3-dibromo-2,7,7-trimethyl-
tricyclo[4.1.1.02,4]octane (385)……………………………………… 64
x