Light-Driven Alkyne gem-Hydrogenation: An Intramolecular Approach to Hoveyda-Grubbs Catalysts

The light-driven gem-hydrogenation of internal alkynes in the presence of [(NHC)(eta(6)-cymene)RuCl2] generates discrete ruthenium carbene complexes. When applied to appropriately designed enyne substrates, the reactive intermediates thus formed will engage the tethered olefin in metathetic ring closure while splitting off a Hoveyda-Grubbs-type complex as secondary carbene. This unconventional approach to these classical catalysts for olefin metathesis rivals existing methodology in that it is safe, short, phosphine-free, and uses readily available starting materials.

Automated summary

The light-driven gem-hydrogenation of internal alkynes in the presence of [(NHC)(eta(6)-cymene)RuCl2] generates discrete ruthenium carbene complexes. These complexes can be used to efficiently perform metathetic ring closure reactions with tethered olefins, while simultaneously producing Hoveyda-Grubbs-type complexes as secondary carbenes. This unconventional approach offers a safe, short, phosphine-free, and easily accessible alternative to existing catalysts for olefin metathesis.