ORGANONICKEL CHEMISTRY IN ORGANIC-SYNTHESIS - SOME APPLICATIONS OF ALKYL AND METALLACYCLIC DERIVATIVES

The Ni-C bonds of stable, square-planar Ni(II)-alkyl and metalacyclic complexes, that contain the strongly basic PMe3 group as the stabilizi ng ligand, are shown to exhibit a very rich insertion chemistry toward a number of unsaturated molecules (CO, CNBu(t), alkynes, CS2, CSNPh,. ..). Heterocumulenes CXY (e. g. CO2, CS2, ...) regioselectively insert into the Ni-aryl bond of the nickelacycle (Me3P)2Ni(CH2CMe2-o-C6H4) 3 to yield unstable intermediate species, able to undergo the subsequen t insertion of CO or CNBu(t). This sequential insertion chemistry prov es to be particularly rewarding and allows the synthesis of a number o f sulfur-containing organic heterocycles.