Telechelic cis‐1,4‐oligoisoprenes through the selective oxidolysis of epoxidized monomer units and polyisoprenic monomer units in cis‐1,4‐polyisoprenes

Telechelic cis‐1,4‐oligoisoprenes were prepared by the selective cleavage of weak epoxidized units (E) in epoxidized cis‐1,4‐polyisoprenes (EPIs) and by the random cleavage of isoprenic units (I) in cis‐1,4‐polyisoprene (PI). In both cases, cleavage by periodic acid (H5IO6) in tetrahydrofuran led to aldehydic and ketonic chain ends. Through variations in the E/(I + E) molar percentage (E%) in the cleavage of EPI and through variations in the H5IO6/I molar percentage (PA%) in the cleavage of PI, a polydispersity index near 2 and a number‐average molecular weight of 2 – 20 × 103 were obtained. The correlation of the degree of scission with E% and PA%, combined with kinetic, led to the proposal of a two‐step mechanism for the H5IO6 cleavage of double bonds.