Reductive Cyclization of Diynes and Enynes Catalyzed by Allyl Platinum N-Heterocyclic Carbene Complexes

Platinum N-heterocyclic carbene (NHC) complexes
have been synthesized and used as precatalysts in the reductive
cyclization of diynes and eynes. 2,5-Dihydrofurans, -pyrroles,
and -cyclopentenes were obtained as reductive cyclization
products from oxygen-, nitrogen-, and carbon-tethered substrates, respectively. The yield and product of the reaction were
highly dependent upon the substrate and the substituent on the
alkyne.