Regio- and stereo-chemical control in the nickel-catalysed addition of HCN to alkynes. A simple synthesis of (E)-2-alkyl-3-trialkylsilylalk-2-enenitriles

By varying the steric bulk of silicon substituents attached to alk-1-ynes it is possible to control, to a high degree, the regiochemical outcome of nickel(0)-catalysed hydrocyanations of alk-1-ynes: the crystal structure of one adduct is included which establishes that the stereochemical outcome of the reaction is a result of addition of HCN to the alkyne to give an (E)-product; overall, these results constitute a simple method for the preparation of (E)-2-alkyl-3-trialkylsilylalk-2-enenitriles.