Catalytic reactions of C3-cyclic olefins in the presence of metal complexes. 4. Ni complexes as catalysts for the [2+2]-cyclodimerization of spiro[2,3]hex-1-ene

Abstract

Ni(0), Ni(I), and Ni(II) complexes, differing in the ligand environment of the central atom, bring about di-, tri-, and oligomerization of spiro[2,3]-hex-1-ene (SH). The most efficient catalyst for the [2+2]-cyclodimerization of SH is NiBr(PPh3)3, which gives virtually a single product, the SH cyclo dimer. It has been found that high conversion and selectivity in the [2+2]-cyclodimerization of SH is achieved by using organoaluminum compounds as catalysts.