Synthesis and evaluation of 1,3-diethyl-2,2-dimethoxymethylcyclohexane, an external electron donor in Ziegler–Natta catalysis

The first synthesis of 1,3-diethyl-2,2-dimethoxymethylcyclohexane starting from the easily available methyl 6-ethyl-2-oxocyclohexanecarboxylate via a process involving the building up of a fourfold carbon by a regiospecific alkylation of a silyl enol ether and the introduction of the ethyl substituent by a carbanionic approach is described. The behaviour of 1,3-diethyl-2,2-dimethoxymethylcyclohexane as external electron donor in high activity supported Ziegler–Natta catalyst is studied. The results presented show that this new donor allows the synthesis of polypropylene with a good isotacticity.