Chowdhury, Sultan (2001) Deep molecular baskets : convergent syntheses of calixnaphthalenes via directed ortho metallation and Suzuki-Miyaura coupling reactions. Doctoral (PhD) thesis, Memorial University of Newfoundland.
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Calixnaphthalenes are a new class of compounds which are analogous to the better-known calixarenes, but have deeper cavities. These compounds, especially the endo calixnaphthalenes e.g., 31 can behave as "molecular baskets" in their abilities to complex with neutral guest molecules such as fullerene. This thesis describes the synthesis of such deep molecular baskets. -- Calixnaphthalene (31 ) was synthesized by self-condensation reactions of 6-tert -butyl-3-(hydroxymethyl)-2-naphthol ( 29 ). Various Lewis acids were evaluated in order to obtain 31 in higher yield. Conformational properties of 31 were studied by VT⁻¹ H NMR experiments in two different deuterated solvents. Alkyl ether derivatives (41a-41b ) of 31 , and also tert -butylcalixnaphthalene-1,3-crown 42 were synthesized, and all compounds were shown by NMR experiments to exist in cone conformations. -- A synthetic route toward the synthesis of the C₂ᵥ -symmetrical "C-12" endo calixnaphthalenes e.g., 35 allowed us to evaluate the efficiency of the Suzuki-Miyaura coupling reactions for various benzylic halides and bromomethylnaphthalenes with phenyl- and naphthylboronic acids. Directed ortho Metallation (DoM) reactions using both n -butyl- and tert -butyllithium were evaluated for the introduction of various functional groups orthoto the hydroxyl group of 2-naphthol, bis(2-hydroxy-1-naphthyl)methane and their derivatives. -- Synthesis of calixnaphthalene (35 ) was achieved using both acid- and base-induced condensation reactions of compound 98 and aqueous formaldehyde solution. Various alkyl ether derivatives ( 113a-113d ) of 35 were obtained, and their conformational properties were studied by NMR experiments. The X-ray crystal structure of113d revealed that it exists in a cone conformation as a clathrate containing two molecules of toluene located in its hydrophobic cavity. -- Calixnaphthalene (114 ), an example of an endo/exo -type calixnaphthalene was synthesized using "2 + 2" Böhmer condensation conditions. Considerable effort was expended to synthesize endo calixnaphthalenes (78-80 ), and other calixarenes containing mixed benzene and naphthalene units (e.g., 116 ) via "2 + 2" and/or "3 + 1" Böhmer conditions. Other unsuccessful attempts were made to synthesize all the possible isomers of endo calixnaphthalenes (35a-c and 107 ) using Suzuki-Miyaura coupling reactions. -- Several approaches towards modifying the lower rim of calixarenes were undertaken in order to deepen their cavities. The hydroxyl groups of 2 were derivatived to triflates 118-121 and also to nonaflate 125 in order to evaluate Suzuki Miyaura, Stille and Pd-catalyzed carbonylative reaction conditions. The first successful syntheses aryl ether derivatives (131-134 and 137-143 ) of 2 were achieved using either Nucleophilic Aromatic Substitution (SN Ar) or Ullmann ether conditions.
|Item Type:||Thesis (Doctoral (PhD))|
|Additional Information:||Bibliography: leaves 221-233|
|Department(s):||Science, Faculty of > Chemistry|
|Library of Congress Subject Heading:||Calixarenes--Synthesis; Supramolecular chemistry|
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