Cyclopolyenic 1,3-diethers wherein the carbon atom in position 2 belongs to a particular cyclic or polycyclic structure containing two or three unsaturations, solid catalyst components and catalysts therefrom, the catalysts comprising the reaction product of: i. a solid catalyst component containing an internal donor; ii. an Al-alkyl compound, and optionally iii. an external donor; the internal donor and/or the external donor being cyclopolyenic 1,3-diethers. The catalysts are useful for the polymerization of alpha-olefins.