Nickel-catalyzed regio- and stereoselective homo 1,4-dialkenylation of conjugated dienes

Article abstract of DOI:10.1016/S0040-4020(97)10205-8

2,3-Dimethyl-1,3-butadiene and cyclic dienes react with β-iodoenones (RI: 3-Iodo-2-cyclohexen-1-one, 5,5-dimethyl-3-iodo-2-cyclohexen-1-one and 3-iodo-2-cyclopenten-1-one) in the presence of Zn and catalytic amount of NiBr₂ to afford the corresponding homo 1,4-addition products in good yields. For 2,3-dimethyl-1,3-butadiene, only the products RCH₂C(CH₃)=C(CH₃)CH₂R with Z geometry were observed. For cyclic dienes, the products observed are RCHCH=CHCHR(CH₂)(n)CH₂ in which the two alkenyl substituents R are cis to each other.