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Organocatalyzed and Uncatalyzed CC/CC and CC/CN Exchange Processes between Knoevenagel and Imine Compounds in Dynamic Covalent Chemistry
Author(s) -
Kulchat Sirinan,
Meguellati Kamel,
Lehn JeanMarie
Publication year - 2014
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201400187
Subject(s) - chemistry , knoevenagel condensation , organocatalysis , malononitrile , imine , catalysis , barbituric acid , covalent bond , bond cleavage , medicinal chemistry , organic chemistry , stereochemistry , enantioselective synthesis
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.