Synthesis, Structure and Catalytic Activity of NHC-AgI Carboxylate Complexes

A general synthetic route was used to prepare 15 new N‐heterocyclic carbene (NHC)–AgI complexes bearing anionic carboxylate ligands [Ag(NHC)(O2CR)], including a homologous series of complexes of sterically flexible ITent ligands, which permit a systematic spectroscopic and theoretical study of the structural and electronic features of these compounds. The complexes displayed a significant ligand‐accelerated effect in the intramolecular cyclisation of propargylic amides to oxazolidines. The substrate scope is highly complementary to that previously achieved by NHC–Au and pyridyl–AgI complexes. Release the kraken! Fifteen new N‐heterocyclic carbene (NHC)–AgI complexes, bearing anionic carboxylate and sterically flexible tentacular (ITent) ligands [Ag(NHC)(O2CR)], have been prepared. The complexes efficiently catalyze the cyclisation of propargylic amides to oxazolidines with a broad substrate scope and show a significant ligand‐accelerated effect, in contrast to previously reported NHC–Au and pyridyl–AgI complexes.