Asymmetrische katalysen: XXIV. Cross-coupling von 1-phenylethylgrignard und vinylbromid mit Ni-katalysatoren optisch aktiver P/N-liganden

Sixteen new N/N, P/N, and P/P chelate ligands, together with NiCl2, were used as in-situ catalysts for the enantioselective cross-coupling of I-phenylethylgrignard and vinylbromide. The N/N ligands give no optical yield in the formation of the product 3-phenyl-1-butene. With the P/N and P/P ligands, 31.9% e.e. can be achieved. The control of optical induction by substituents in the skeleton of the P/N ligands is in accord with the results of conformational analyses of stable model complexes.