الفهرس 
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Abstract
Dienone-phenol rearrangement is considered as one of the most convenient methods that give an access to multi-substituted phenols. It has several applications in pharmaceutical industry. The rearrangement of 4,4-disubstituted 2-hydroxy cyclohexa-2,5-dienones and their derivatives affords disubstituted catechols under acidic conditions or corresponding o-fluorophenols under deoxyfluorination conditions. However, the factors controlling the migration still needs further investigation. In this study, considering that disubstituted catechols are important structural motifs involved in various pharmaceuticals and agrochemicals along with the significance of fluorine in drug discovery, I focused on finding a way to manipulate the migration tendency either towards C3- or C5- carbons, which in turns will be useful to afford disubstituted catechols or o-fluorophenols in a regioselective manner for further biological evaluation. The migration of 4,4-disubstituted 2-hydroxycyclohexa-2,5-dienones under acidic conditions always proceeded towards more electron deficient C5-carbon affording 4,5-disubstitued catechols. I aimed to develop a method to manipulate the migration towards C3-carbon to afford the hardly accessible 3,4-disubstituted catechols, especially that up to date, the synthetic protocols are very limited in terms of yield, regioselectivity and substrate scope. My first trial was to investigate effects of protecting groups (PGs) attached to the C2-hydroxyl moiety of dienones on the migration regioselectivity, which had not been studied before. I found that the ratio of the C3-migration products increased using electron withdrawing groups. In particular, a combination of a fluorosulfonyl group (PG = SO2F) with a suitable Brønsted acid or Lewis acid afforded the desired 3,4-disubstituted catechols for the first time. However, they were always obtained along with 4,5-disubstituted catechols and their yields were up to 50%. In order to increase the electron-withdrawing effect of PG, I attempted a reaction of 2-hydroxydienones with hypervalent iodine reagents to find that 3,4-disubstituted catechols were obtained in up to 81% yield with exclusive regioselectivity after the one-pot reduction of the in situ generated ortho-quinones. Applicability to different substrates was demonstrated. The migration of 4,4-disubstituted 2-hydroxycyclohexa-2,5-dienones under deoxyfluorination conditions was known to proceed towards C3- and C-5 carbons with poor regioselectivity. Throughout this work, I studied to control the migration towards C5-carbon exclusively to afford 4,5-disubstituted o-fluorophenols via acid-mediated migration of difluoro intermediates, generated from dienones under deoxyfluorination conditions, among which the protection of the C2-hydroxyl group by a perfluoroalkylsulfonyl group, such as Tf and Nf groups, was crucial. Application to other substrates was demonstrated. In order to get further insight into the similarity between 2-hydroxycyclohexa-2,5-dienones and related difluorides following acid-mediated migration in terms of regioselectivity, I studied the effect of different PG attached to the C2-hydroxyl group of different difluorides. I found that the dienones and related difluorides showed different behavior, where difluoride migration always proceeded preferentially towards C5-carbon affording 4,5-disubstituted o-fluorophenols regardless the electronic effect of PG. In conclusion, I could control the dienone-phenol rearrangement of 4,4-disubstituted 2-hydroxycyclohexa-2,5-dienones to afford 3,4-disubstituted catechols in a perfect regioselectivity for the first time. Furthermore, the migration was controlled under deoxyfluorination conditions to afford 4,5-disubstituted o-fluorophenol exclusively. Both methodologies would allow an access for medicinal chemists for biological investigation of these compounds. I also found out that the electronic effect of PG attached to the C2-hydroxyl moiety is different in case of dienones and related difluorides.