Identifier: TDX:2771
Authors: Miralles Prat, Núria
Abstract:
This thesis is about the use of diboron and gem-diborylalkane reagents in catalysis in order to introduce one or more boryl fragments to unsaturated substrates. For that reason, different borylation reactions have been employed in organocatalytic conditions, activating the borane reagent with an alkoxide formed in situ by the combination of methanol and base. This is the case of aryl substitution of hypervalent iodionium salts, in which even in the absence of base the reaction takes place due to the participation of counterion. The diboration of alkenes is another example of organocatalysis but with incorporation of a non-symmetrical diboron reagent such as BpinBdan, providing 1,2-diborated products with two different boryl units. Finally, it has been also explored the allylic substitution reaction in two manners: the organocatalytic, that applied to allylic and propargylic alcohols using B2pin2 as diboron reagent generates allylboronate compounds and, using harsher reaction conditions, it could be also obtained triborated compounds. In the other approach a copper catalyst was used to increase the nucleophilic character of boron atom, and employing both 1,1-diborylmethane and B2pin2 reagents to be added to vinyl cyclic carbonates afforded homoallyl and allyl boronate products, respectively. It has been also studied the borylation of sterically encumbered aryl halides through Pd catalysts, and the object molecule has been analyzed by non-conventional characterization methods, such as AFM. In all cases, it has been obtained organoborated molecules with high scientific interest due to the versatility of carbon-boron bond, as it has also been exemplified in this thesis.
Repositori URV