Asymmetric Ketone Hydrogenation

By: Josephine Nakhla, chemfiles volume 9 article 2

Mikami and co-workers reported an asymmetric ketone hydrogenation that utilizes an achiral benzophenone ligand (2,2’-bis(diphenylphosphino)benzophenone, DPBP) chelated to a ruthenium catalyst, followed by addition of (1S,2S)-(-)1,2- diphenylethylenediamine (S,S-DPEN). The levels of enantioselectivity observed with the benzophenone-based catalyst are superior to those observed with BINAP-based catalytic systems. When the hydrogenation of 1’-acetonaphthone was examined with 2,2’-bis(diphenylphosphino) benzhydrol as the ligand in place of benzophenone, the enantioselectivity observed was lower than that observed with 2,2’-bis(diphenylphosphino)benzophenone) (Table 1).1


Table 1.

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References

  1. Mikami, K. et al. Org. Lett. 2006, 8, 1517.

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