Hydrogermylation initiated by trialkylborohydrides: a living anionic mechanism

Abstract

Sodium trialkylborohydrides were found to be selective catalysts for the hydrogermylation of aromatic alkenes. Addition of phenylgermane and diphenylgermane in the presence of 10 mol% of NaHB(sec-Bu)3 proceeded in a highly selective manner to give – in contrast to the analogous hydrosilylation process – β-germylated products. The nature of this process was explained with the aid of DFT calculations and it was proposed that the mechanism proceeds via a trisubstituted germanide anion whose attack on the terminal vinyl carbon is the source of selectivity.

Visible-Light-Driven Silyl or Germyl Radical Generation via Si–C or Ge–C Bond Homolysis

“…1 Thus, there is considerable interest in the development of efficient and practical methods for the formation of silyl radicals, which have been of great interest for widespread applications of organosilicon chemistry. 2,3 Thermo-induced HAT (hydrogen atom transfer) reactions of silicon hydrides (R 3 SiH) that release R 3 Si• were reported as early as the 1940s, 1a leading to the discovery of the hydrosilylation reaction. Since then, R 3 SiH has been predominantly used as a silyl radical precursor for many innovative transformations.…”