CYCLIZATION OF TYL-N-(ORTHO-CHLOROPHENYL)-4-AMINOBUT-2-ENENITRILE WITH ZEROVALENT NICKEL-COMPLEXES - CONFORMATIONAL-ANALYSIS OF THE N-3-CYANOPROP-2-ENYL CHAIN

Cyclization of etyl-N-(ortho-chlorophenyl)-4-aminobut-2-enenitrie with zerovalent nice complexes, prepared from bis(acetylacetonate)nickel(I I), with either pyridine or triphenylphosphine as ligands, and triethy laluminium as reducing agent has been carried out. The alpha-methylene protons show a diastereotopic effect which could be explained by a ri gid bridged hydrogen bound through the oxygen atom of the acetanilide group to one of the alpha-methylene protons and partially hindered rot ation around the N-phenyl bond, due to the ortho-substitution. Conform ational analysis of the fragments of the N-3-cyanoprop-2-enyl chain ha s been carried out using the Sternhell treatment.