The Stereochemistry of Organometallic Compounds. XXII The Stereochemistry of Metal-Catalysed Hydrogen Cyanide Addition to Olefins

Reactions of (E)-3, 3-dimethyl(l, 2-D₂)but-1-ene with hydrogen cyanide and of (E)-3, 3-dimethyl-(1-D)but-1-ene with deuterium cyanide have been shown to proceed in a completely stereospecific cis fashion when a catalyst system based on Pd(diop)₂ was used. Reaction between 4-t-butylcyclo-hexene and deuterium cyanide with the catalyst system gave only the equatorial nitriles trans-4-t-butylcyclohexane-1-carbonitrile and cis-3-t-butylcyclohexane-1-carbonitrile with cis incorporation of deuterium. Use of a catalyst system based on Ni[P(OPh)₃]₄and zinc chloride led to significant amounts of isotopic exchange and rearrangement. These results are compared with those from hydroformylation of the olefins, and the mechanism of hydrocyanation is discussed.