Enantioselective Hydrogenation of Endocyclic Enones: the Solution to a Historical Problem†

Main observation and conclusion The enantioselective hydrogenation of endocyclic enones has been a historical problem for homogeneous catalysis. We herein report an efficient method to reduce endocyclic enones with molecular hydrogen. Catalyzed by a rhodium/Zhaophos complex, a variety of enones with five-, six- or seven-member ring were hydrogenated with high enantioselectivity (92%-99% ee). Excellent chemo- and enantioselectivity demonstrated this method was successfully applied in the enantioselective hydrogenation of citral to produce enantio-enriched citronellal.

Automated summary

In this study, an efficient method for reducing endocyclic enones with high enantioselectivity using molecular hydrogen catalyzed by a rhodium/Zhaophos complex is reported. This method demonstrated excellent chemo- and enantioselectivity and was successfully applied in the enantioselective hydrogenation of citral to produce enantiomer-enriched citronellal.