The effects of multiple-benzannelation on aromatic/antiaromatic methano -bridged annulenes.
Item
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Title
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The effects of multiple-benzannelation on aromatic/antiaromatic methano -bridged annulenes.
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Identifier
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AAI9986340
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identifier
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9986340
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Creator
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Hsu, Shu-Ya.
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Contributor
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Adviser: Klaus G. Grohmann
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Date
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2000
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Organic
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Abstract
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In order to assess the effect of benzannelation on the aromaticity/antiaromaticity of methano-bridged [10], [12] and [16] annulenes, compounds I through IV were targeted. Several routes including Diels-Alder cyclization, Wittig olefination, McMurry reaction and Ring Closing Metathesis (RCM) were investigated for the synthesis of compounds I to IV.; Compound I: 3,4-benzo-1,6-methanol[10]annulene Compound II: 3,4,8,9-dibenzo-1,6-methano[10]annulene Compound III: 3,4-benzo-1,6-methano[12]annulene Compound IV: 3,4,11,12-dibenzo-1,6:9,14-bismethanol[16]annulene .;In this dissertation, I will present the synthesis of III and IV as well as our attempts to obtain I and II. The generation of 8,10-dimethylene-bicyclo[5,4,0]undeca-2,4,6,11-tetraene 65 and its Diels-Alder reaction will also be presented.;Ring Closing Metathesis (RCM) of the protected alcohols 100a and 100b led to a new approach towards 3,4-benzo-1,6-methano [12] annulene III. The scope and limitation of this new general synthesis have been investigated. This new method in essence is also an efficient synthesis of the parent 1,6-methano[12]annulene, previously obtained by Vogel et al. through an elegant but lengthy synthesis.;The starting material in all cases is 3,4-benzcycloheptatriene-1,6-dialdehyde 63, prepared via a one step aldolcyclization from glutaraldehyde and o-phthalaldehyde.;The results of our comparative structural, chemical and spectroscopic investigation of these benzannelated systems with respect to their aromaticity/antiaromaticity will be presented.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
