Low Coordinate Germanium(II) and Tin(II) Hydride Complexes: Efficient Catalysts for the Hydroboration of Carbonyl Compounds

This study details the first use of well-defined low-valent p-block metal hydrides as catalysts in organic synthesis. That is, the bulky, two-coordinate germanium (II) and tin (II) hydride complexes, L (†) (H) M: (M = Ge or Sn, L (†) = -N (Ar (†) ) (SiPr (i) 3), Ar (†) = C6H2C (H) Ph22Pr (i) -2, 6, 4), are shown to act as efficient catalysts for the hydroboration (with HBpin, pin = pinacolato) of a variety of unactivated, and sometimes very bulky, carbonyl compounds. Catalyst loadings as low as 0. 05 mol % are required to achieve quantitative conversions, with turnover frequencies in excess of 13 300 h (-1) in some cases. This activity rivals that of currently available catalysts used for such reactions.