Reactions of allene and aldehydes; adduct formation in the presence of nickel complexes

Abstract

Reaction of the bis-π-allylnickel complex formed from three moles of allene with acetaldehyde or acrolein and subsequent treatment with aqueous potassium cyanide has been demonstrated to give two isomeric alcohol adducts in a ratio of ca. 7 : 1. The specificity of reaction has been suggested to be a consequence of the σ, π-character of the bis-π-allylnickel complex with addition at the σ-allyl system. The reaction was enhanced by the addition of organophosphine ligands and dimethyl formamide and depressed by triphenyl phosphite. Hydrocarbons formed by interaction of the solution containing the allene-nickel complexes with aqueous potassium cyanide has yielded information on the structures of these bis-π-allylnickel complexes.