This report is an investigation of regioselectivity in transition metal catalyzed ring-opening reactions involving unsymmetrical oxabicycles, specifically with a substituent at the C1 position. This report also provides the details of the work conducted towards the preparation of various oxanorbornadienes and their precursors. A large number of reactions have been developed using various transition metal catalysts on oxabicyclic alkenes to form functionalized organic scaffolds. However, most of the literature is limited to symmetrical substrates. Introduction of a substituent at the bridgehead carbon of the bicyclic ring makes the molecule unsymmetrical. The implications of loss of the plane of symmetry in C1 substituted oxabicyclic ring are manifested in interesting ways during various metal catalyzed reactions. The fundamental basis for the current work is to study the consequences of transition metal catalyzed ring opening reactions of unsymmetrical bicyclic alkenes. The reactivity of a wide range of C1 substituted benzoxanorbornadienes and oxanorbornadienes in palladium and nickel-catalyzed ring opening reactions was explored. The palladium catalyzed ring opening reaction of both electron rich and electron deficient C1 substituted benzoxanorbornadienes are optimized. The ring opening reactions with electron withdrawing C1 substituent resulted in formation of substituted naphthalene-1-carboxylic acid methyl ester derivatives in up to 85% yield. Electron donating substituents on the C1 position of benzoxanorbornadiene led to the formation of substituted cis-1,2-dihydronaphthol rings in excellent yields. Palladium catalyzed ring opening reactions were also explored with a wide range of aryl iodides and halobenzenes. The electronic and steric effects of the substituent at the C1 position of oxabicyles were also investigated. The nickel catalyzed ring opening reactions resulted in formation of inseparable regioisomeric mixtures of products. However, it was found that the nickel catalyzed ring opening of 1-methoxycarbonyl-7-oxabenzonorbornadiene occurred regioselectively affording a single product. A scalable procedure for preparation of large quantities of 2-bromofuran was developed. 2-Aryl furans were prepared using Suzuki cross coupling protocols of 2-bromofuran with aryl boronic acids whereas 2-alkyl furans were prepared by iron catalyzed cross coupling reaction of 2-bromofuran with various alkyl and cycloalkyl Grignard reagents. The 2-substituted furans were used for the preparation of novel C1 substituted benzoxanorbornadiene and oxanorbornadienes.

En vue d’effectuer des préparations sélectives de composés hétérocycliques, une étude de la synthèse et de la réactivité de 7-oxanorborna-2,5-diènes portant des groupes électroattracteurs différents sur les positions 2 et 3 a été réalisée. Ces composés sont des formes masquées de composés acétyléniques dissymétriques.Dans un premier temps, nous avons optimisé une nouvelle méthode de synthèse sélective d’acétylènedicarboxylates dissymétriques par mono-transestérification d’acétylènedicarboxylates de dialkyle symétriques avec des alcools en présence de la lipase de Candida rugosa. Cette méthode nous a permis d’obtenir les diesters dissymétriques avec de bons rendements et une haute sélectivité a priori inattendue.Dans un second temps, nous avons développé des synthèses régiosélectives de dérivés de l’acide 7-oxanorborna-2,5-diène-2,3-dicarboxylique selon deux stratégies. Dans une première approche, une réaction de Diels-Alder intramoléculaire entre un furane et un composé acétylénique reliés par une agrafe siliciée a été réalisée, suivie d’une coupure des liaisons Si-C. Cette cycloaddition [4+2] s’effectue uniquement en présence de MeAlCl2 avec des rendements moyens. Dans certains cas, la coupure des liaisons Si-C conduit aux diesters désirés. Dans une deuxième approche, une mono-saponification d’oxanorbornadiène-2,3-dicarboxylates de dialkyle a permis d’accéder régiosélectivement à des monoacides et des réactions de couplage avec des amines ou des alcools ont conduit sélectivement à des dérivés présentant deux groupes électroattracteurs différents.Dans une dernière partie, nous avons effectué la préparation régiosélective de 3-pyrrolines par cycloaddition [2+3] d’un ylure d’azométhine suivie d’une réaction de rétro-Diels-Alder à partir des 7-oxanorbornadiènes comportant deux groupes électroattracteurs différents. La préparation aisée de 3-pyrrolines condensées non décrites dans la littérature a été obtenue par formation inattendue d’un motif succinimide dans le cas des amidoesters.En conclusion, il apparaît que la présence du groupe éthyle en tête de pont des 7-oxanorborna-2,5-diènes semble suffisante pour contrôler la régiosélectivité de ces cycloadditions. / In order to selectively prepare heterocyclic compounds, a study of the synthesis and reactivity of 7-oxanorborna-2,5-dienes with different electron-withdrawing groups on the 2 and 3 positions was performed. These compounds are masked forms of unsymmetrical acetylenic compounds. At first, we have optimized a new method for the selective synthesis of unsymmetrical diesters by transesterification of symmetrical dialkyl acetylenedicarboxylates in the presence of Candida rugosa lipase. This unexpectedly highly selective method allowed us to obtain unsymmetrical acetylenedicarboxylates in good yields.In a second part, we have developed a regioselective synthesis of 7-oxanorborna-2,5-diene-2,3-dicarboxylic acid derivatives according to two strategies. In one approach, an intramolecular Diels-Alder reaction between a furan and an acetylenic compound connected by silicon-containing tethers was performed, followed by a cleavage of the Si-C bonds. This [4+2] cycloaddition was carried in the presence of a Lewis acid, only MeAlCl2 gave the expected product and so in moderate yields. In most cases, the cleavage of Si-C bonds leads to the desired diesters. In a second approach, a mono-saponification of dialkyl oxanorbornadiene-2,3-dicarboxylates provided access regioselectively to mono-acids and coupling reactions with amines or alcohols selectively led to poly-functionalized products containing two different electron-withdrawing groups.In the last part, we have regioselectively prepared 3-pyrrolines by [2+3] cycloaddition of an azomethine ylide to 7-oxanorbornadienes bearing electroattracting groups followed by a retro-Diels-Alder reaction. An easy synthesis of previously unknown condensed 3-pyrrolines was obtained by formation of an unexpected succinimide pattern from amidoesters. In conclusion, it appears that the presence of an ethyl group on the bridgehead carbon atom of 7-oxanorborna-2,5-dienes seems sufficient to control the regioselectivity of these cycloadditions.