Continuous Photochemical Generation of Catalytically Active [CpRu]+ Complexes from CpRu(η6-C6H6)PF6

Organic Letters 3(24), 6414-6417, DOI: 10.1021/ol2027015

Inter- and intramolecular ene–yne coupling reactions catalyzed by a species generated in situ via photolysis of CpRu(η6-C6H6)PF6—an inexpensive, readily available, and shelf-stable complex—have been demonstrated under conditions of continuous flow. Importantly, the catalyst can be recovered quantitatively at the end of the reaction. Various functional groups are tolerated by the reaction, which affords skipped diene products in high yields.