A Ligand Effect in the Reaction between Butylmagnesium Bromide and Allyl Chloride in the Presence of Transiton Metal Salts

Abstract

The reaction of butylmagnesium bromide and allyl chloride in the presence of nearly equal amount of the nickel or cobalt complexes coordinated with phosphine yielded large proportions of octane (56-v61%) and 1, 5-hexadiene (40N59%), which is in marked centrast to those propylene 70%e and butenes 71% obtainedin the presence of catqlytic amount of the metal chlorides.
The addition of hexamethylphosphortriamide (2 equives to BuMgBr) to the latter reaction conditiengave the similar effect as in the case of the coordinated metal complexes.
The principal effect of the ligand was deduced to lie in the stabilization of thedibutyl metal interrmediate from'butylmagnesium bromide rather than rr-allylmetal intermediate.
TheLdependence of the products on the quantity of a, a'-dipyridyl nickel and cobalt chlorides showed that the ligand effect becomes appreciable only at a higher concentration ( 10-S) of the metal complexes.