Homogeneous Isomerization of 1-Butene Catalyzed by [MX2(PR3)2]–NaBH4 Systems (M=Co, Ni, X=Halides, SCN, PR3=PPhnEt3−n)− Acceleration by Phosphine Addition and Stereoselectivity

Abstract

Abstract The stoichiometric or a little excess amount of NaBH4 was treated with [MX2(PR3)2] (M=Co, Ni, X= halides, SCN, PR3=PPhnEt3−n) in THF–1,2-dimethoxyethane to form monohydride species which were active for isomerization of 1-butene. The reaction was accelerated by excess PPh3 in [CoX2(PPh3)2]–NaBH4 systems. Other catalytic systems have optimum ratios of excess phosphine to metal for getting maximum activities. Thiocyanate–metal complexes are the most active in each Co– and Ni–catalyst system. Cisselectivity depends on the cone angle of PR3, the size of anion ligands, and the congested structure of complexes.