Thermal decomposition of trans-chloro(2-allylphenyl)bis(triethylphospine)nickel(II)☆

Abstract Thermolysis of trans -chloro(2-allylphenyl)bis(triethylphosphine)nickel(II), I, in tetrachloroethylene has afforded indene as the major hydrocarbon product along with lesser amounts of allylbenzene and trans -β-methylstyrene. Organonickel products were trans -chloro(trichlorovinyl)bis(triethylphosphine)nickel(II), II, chloro[2-( trans -propenyl)phenyl]bis(triethylphosphine)nickel(II), III, and trans -dichlorobis(triethylphosphine)nickel(II). Compound III was the major product from thermolysis of I in benzene. Chloro[2-( cis -propenyl)phenyl]bis(triethylphosphine)nickel(II), IV, and III could be synthesized independently by treatment of chloro-2-( cis -propenyl)benzene and chloro-2-( trans -propenyl)benzene, respectively, with nickel acetylacetonate and triethylaluminium in the presence of triethylphosphine. Thermolysis of I in benzene containing allylbenzene led to the formation of trans -β-methylstyrene. The thermolysis of I in benzene in the presence of cis -1,4-hexadiene caused the skeletal rearrangement of the diene to trans -2-methyl-1,3-pentadiene. A catalyst derived from ethylenebis(triphenylphosphine)nickel(0) and hydrogen chloride isomerized allylbenzene to trans -β-methylstyrene.