sec-Butyllithium combined with a new family of ligands, (i.e., lithium silanolates), has been used to initiate the ligated anionic polymerization of n-butyl acrylate (BuA) in toluene at low temperature. Compared to other mu-ligands, sBuMe(2)SiOLi is a more efficient stabilizer of the active centers. Thus, under selectively chosen reaction conditions, the polymerization proceeds quantitatively at -40 degrees C, producing a high-molecular-weight polymer with narrow-molecular-weight distribution (<(M-W)over bar>/<(M-n)over bar>, < 1.2). When the copolymerization of BuA is initiated by a living {PMMALi, 5.sBuDLi} in toluene at -78 degrees C, the experimental data agree with a well-controlled block copolymerization reaction, since the final molecular-weight distribution is very narrow (<(M-W)over bar>/<(M-n)over bar> less than or equal to 1.1) and the polymerization efficiency very high.