2014/09/01 by Sirinan Kulchat, Kamel Meguellati, Jean‐Marie Lehn +1 · 3 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · #Chemical Synthesis and Analysis #Asymmetric Synthesis and Catalysis #Asymmetric Hydrogenation and Catalysis
paper · doi:10.1002/hlca.201400187
Abstract Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by CC and CN bonds through reversible double‐bond formation, and cleavage in CC/CC and CC/CN exchange processes. The reversibility of the Knoevenagel reaction has been explored, and CC/CC C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as L ‐proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L ‐Proline is also used to catalyze the reversible CC/CC exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (CC/CN exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on CC/CC and CC/CN exchange systems.