Silver(I)-carbene complexes/ionic liquids: novel N-heterocyclic carbene delivery agents for organocatalytic transformations.
[reaction: see text] N-Heterocyclic carbene (NHC) complexes with silver were investigated as sources of unsaturated NHC carbene catalysts via thermal decomposition. The NHC complex (1-ethyl-3-methylimidazol-2-ylidene)silver(I) chloride is an ionic liquid, and was found to catalyze the ring-opening polymerization of lactide at elevated temperatures to give narrowly dispersed polylactide of predictable molecular weight. Silver-carbene complexes can also be used for the catalysis of small molecule transesterification reactions. Thermolysis of the silver complexes in the presence of CS(2) yielded the zwitterionic CS(2) adducts of the carbene, implicating the intermediacy of the free carbene in these reactions.
Sentman
Alan C
AC
IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
Csihony
Szilárd
S
Waymouth
Robert M
RM
Hedrick
James L
JL
D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006838:Hydrocarbons; D008697:Methane / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013696:Temperature
D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D009942:Organometallic Compounds; C030011:carbene; D012834:Silver; D008697:Methane