Abstract Nickela-compounds with a five-membered ring, 4, are formed on Ni 0 from CO 2 and alkenes in the presence of the heterodifunctional ligand (cyclo-C 6 H 11) 2 PCH 2 CH 2- 2-pyridyl (2). A ring contraction occurs on addition of a promoteor, such as BeCl 2, or on heating. The greater reactivity of the nickela-complex with a four-membered ring, 6, can be used in the former reactions with CO 2, CO or CH 2 CH 2. Such a sequence of reactions ...
