Quinone methides, generation water, nucleophilic aromatic substitution

The quinone methide 48 was generated by nucleophilic aromatic substitution of water at Me-48+ as shown in Scheme 23,89 and its reaction with solvent and added nucleophiles studied in water and in 50/50 (v/v) H20/trifluoroethanol at 25°C.4,67,89,91 The addition of a pair of strongly electron-deficient q -CF3 groups to the parent unsubstituted pura-quinone methide p-1 should increase the... 

Generation of quinone methides by nucleophilic aromatic substitution of water at carbocations 59... 

During my early years as an assistant professor at the University of Kentucky, I demonstrated the synthesis of a simple quinone methide as the product of the nucleophilic aromatic substitution reaction of water at a highly destabilized 4-methoxybenzyl carbocation. I was struck by the notion that the distinctive chemical reactivity of quinone methides is related to the striking combination of neutral nonaromatic and zwitterionic aromatic valence bond resonance structures that contribute to their hybrid resonance structures. This served as the starting point for the interpretation of the results of our studies on nucleophile addition to quinone methides. At the same time, many other talented chemists have worked to develop methods for the generation of quinone methides and applications for these compounds in organic syntheses and chemical biology. The chapter coauthored with Maria Toteva presents an overview of this work. 

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