Understanding iodine (I/III) catalysis: From racemic to enantioselective transformations

Identifier:  TDX:3297

Handle: https://hdl.handle.net/20.500.11797/TDX3297

Authors:  Cots Fargas, Eric

Abstract:
mitad de carbonos quirales que sus antecesores demostró buenos rendimientos en la reacción de diaminación. En el caso de los excesos enantioméricos de las diaminas, se mantuvo la mayor parte de la enantiodiferenciación que los catalizadores con simetría C2 eran capaces de inducir en las diaminas finales. In this thesis are described recent advances in the field of iodine (I/III) catalysis. In particular, this chemistry is used for the formation of new C-N bonds, in search of greener alternatives to the existent methodologies for the formation of racemic and enantiopure 1,2-diamines. These compounds are relevant for their biological role and in the fields of organic and pharmaceutical chemistry. Recently, the chemistry of hypervalent iodine (III) and iodine (I/III) catalysis have been proposed as adequate ways for the formation of diamines. Initially, a new racemic catalytic diamination was developed, which allowed the diamination of styrenes in good yields in a practical way and without the use of stochiometric hypervalent iodine reagents. Bismesylamide and Bistosylamide could be incorporated as nucleophiles for the diamination reaction. Afterwards, a scale-up of the synthesis of Ishihara-Muñiz pre-catalysts was performed. During this upscaling, a meso-form of the pre-catalyst for the diamination reaction was detected. When the formation of this species could be avoided, the diamines were obtained in the highest ever reported ee using hypervalent iodine chemistry.