Ni(ethylhexanoate)2/nligand/Et2AlCl catalyzed cycloisomerization of 1,6-heptadienes to cyclopentane derivatives

A series of Ni(OEtHex)2/phosphine/Et2AlCl systems were used as cycloisomerization catalysts of various 1,6-heptadienes. The best results were obtained with the catalytic system using triphenylphosphine as a ligand. The cycloisomerization with this system afforded the corresponding methyl(methylene)cyclopentane derivatives with high selectivity (40–99%) and in good overall yields of the cyclopentane derivatives (90–96%). The cycloisomerization proceeded also with other derivatives possessing 1,6-diene moiety giving the corresponding methyl(alkenyl)cyclopentane derivatives in good yields (33–90%).

Graphical abstractA series of Ni(OEtHex)2/phosphine/Et2AlCl systems were used as cycloisomerization catalysts of various 1,6-heptadienes to methyl(alkenyl)cyclopentane derivatives in good yields (33–90%).Figure optionsDownload full-size imageDownload as PowerPoint slide