Hydrogen-bonding ferrocene derivatives for molecular recognition and organocatalysis

[摘要] The aim of this project was to prepare novel ferrocene-based Hydrogen-bonding receptors and to study them in the electrochemical sensing of neutral compounds and in organocatalysed transformations. The synthesis and characterisation of 2-ferrocenyl oxazoles via gold chemistry to access a new H-bonding motif for electrochemical sensing was successfully achieved. However the targeted structure bearing a secondary amine at the 4-position of the oxazole, was found to be highly unstable and unsuitable for sensing applications. Further studies on ferrocene-based H-bonding systems towards their application in asymmetric organocatalysis were also carried out. Different chiral and achiral ferrocene-(thio)ureas were prepared and tested in four organic reactions. Their performances in the Henry and in the Morita-Baylis-Hillman reactions gave acceptable yields but did not show significant enantioselectivities. A bi-functional ferrocene-thiourea was found to be effective in the enamine co-catalysed aldol reaction of acetone and \(trans-β\)-nitrostyrene, and in the double Michael cycloaddition of ω-nitropentenoate methyl and \(trans-β\)-nitrostyrene, leading to a tetrasubstituted cyclopentane. The H-bonding properties of the ferrocene-(thio)ureas with carboxylates was also studied by \(^1\)H NMR spectroscopy. Finally, approaches towards the preparation of ferrocene-based boronate-ureas were investigated.

[发布机构] University:University of Birmingham;Department:School of Chemistry

[关键词] Q Science;QD Chemistry