Catalytic system for the stereospecific polymerization of dienes and use thereof in a process for synthesizing diene polymers

A bimetallic catalytic system consisting of the metallic components of formulae:

• RLi and Ca(AR′y)2(L)x in which:
• R represents a substituted or unsubstituted C1-C10 aliphatic radical, a substituted or unsubstituted C6-C20 aromatic radical, a diene prepolymer or a substituted or unsubstituted C1-C10 heteroaliphatic radical;
• A denotes a nitrogen atom N or a carbon atom C;
• y depends on the valency of A and has the value 2 when A is N and the value 3 when A is C;
• each R′ represents, independently of one another, a substituted or unsubstituted C5-C10 aliphatic radical, a substituted or unsubstituted C6-C20 aromatic radical, a substituted or unsubstituted silyl radical, a C1-C10 aliphatic radical substituted by at least one substituted or unsubstituted silyl radical, a C6-C20 aromatic radical substituted by at least one substituted or unsubstituted silyl radical;
• L represents a ligand;
• and
• x is a number ranging from 0 to 4.