An intriguing, facile, and efficient oxidation and cyclization
of alkynes catalyzed by Pd(OAc)2 in a fluorous biphasic
system of N,N-dimethylacetamide
(DMA) and perfluorodecalin directly with molecular oxygen is described,
which opens an efficient access to tetrasubstituted furans. Under
the optimized conditions, intermolecular reaction between diverse
alkynes provides the corresponding mixture of regioisomers with
appreciable selectivity. Intramolecular oxidation and cyclization
of alkynes are also successfully demonstrated. The reaction proceeds
efficiently under mild conditions with atmospheric oxygen as the
sole oxidant.
perfluorodecalin - molecular oxygen - alkynes - palladium-catalyzed - oxidation