Trans- and cis-Selective Lewis Acid-Catalyzed Hydrogermylation of Alkynes

Significance

The stereoselective formation of alkenes is an important organic transformation. This represents the first Lewis acid-catalyzed stereoselective hydrogermylation to date. Hydrogermylation of simple alkynes resulted in trans-alkene products, while the hydrogermylation of propio­lates gave cis-alkene products. Adducts of this reaction (both trans and cis) were produced in extremely good yield (majority >99%) and complete selectivity. The transformation of the vinyl metal species to the corresponding vinyl halide (I or Br) was found to occur in high yields with retention of geometry.