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A General and Versatile Approach to Thermally Generated N ‐Heterocyclic Carbenes
Author(s) -
Nyce Gregory W.,
Csihony Szilard,
Waymouth Robert M.,
Hedrick James L.
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400196
Subject(s) - carbene , adduct , chemistry , catalysis , thermal decomposition , polymer chemistry , polymerization , chloroform , transesterification , organic chemistry , combinatorial chemistry , medicinal chemistry , polymer
The synthesis of N ‐heterocyclic carbene (NHC) adducts by condensation of diamines with appropriately substituted benzaldehydes is described. This simplified approach provides the NHC adduct without first having to generate the carbene followed by its protection. These adducts undergo thermal deprotection to generate N ‐heterocyclic carbene in situ. Adduct decomposition temperatures were investigated as a function of catalyst structure by using thermal analysis and spectroscopic techniques. Importantly, unlike adducts derived from chloroform, the new pentafluorobenzene‐based adducts are more readily prepared and are stable at room temperature. The utility of these adducts as organic catalyst precursors for living ring‐opening polymerization (ROP) of lactide, transesterification reactions, and the synthesis of N ‐heterocyclic carbene ligated organometallic complexes is also described.