Ferrocene As A Scaffold For Novol Bifuntional Amine-thiourea Organocatalysts And Its Application In Asymmetric Michael Addition

Bifunctional amine-thioureas, in the past decade, have witnessed a greatdevelopment in the asymmetric organocatalysis. Generally, the known bifunctionalamine-thioureas are derived from1,2-diamine, cinchona-alkaloid and binaphthylderivatives. Ferrocene is a privileged backbone for the construction of chiral ligandsin the metal catalysis due to its characteristics like adequate rigidity, easyderivatization and crystallization, as well as stability. However, it has not beenexploited as a backbone of organocatalysts.In this thesis, ferrocene is used as a scaffold of bifunctional amine-thioureas forthe first time. We envisioned that, in the ferrocene-based bifunctional amine-thioureas,the rigid, bulky, planar and carbon-centered chiral ferrocenemoiety provided effective spatial arrangement, and should be an ideal scaffold for organocatalysts, allowing thecatalytic transformation with excellent enantioselectivity. The main contents of thethesis include the following two parts:1. A simple and readily accessible prototype of the ferrocene-based bifunctionalamine-thiourea was synthesized from Ugi’s amine, p-toluenesulfonyl chloride,sodium azide and isothiocyanate. The structure of the catalyst was confirmedby1H NMR,13C NMR and HRMS.2. The ferrocene-based bifunctional amine-thiourea was initially applied to theasymmetric Michael addition of acetylacetone to nitroolefins, givingR-isomers in high yield and the enantioselectivity of up to96%ee with10mol%catalyst and toluene as solvent in60h.This work showed that the ferrocene-based bifunctional amine-thiourea was veryeasily accessible and exhibited excellent enantioselectivity in the asymmetric Michaeladdition of acetylacetone to nitroolefins, giving the enantioselectivity of up to96%ee.The preliminary results indicate that, in accord with metal catalysis, ferrocene couldbe an excellent scaffold for chiral organocatalysts.