Synthesis of 3,4-dihydroxyphenyl-containing polymeric materials from 1,2-polybutadiene and eugenol via thiol—ene addition

In a search for routes to new promising adhesive materials, 3,4-dihydroxyphenyl groups were introduced for the first time into syndiotactic polybutadiene (1,2-unit content >90%). Two ways of introduction were studied: cross metathesis and thiol—ene addition. Eugenol, an available product of plant origin, was used as a source of 3,4-dihydroxyphenyl groups following the protection of its oxygen-containing groups with Et3SiH in the presence of B(C6F5)3) as a catalyst. A cross metathesis reaction of polybutadiene with modified eugenol in the presence of the Grubbs catalysts of different generations resulted in considerable degradation of the polymer into the corresponding low-molecular-weight products. A new approach involving thiol—ene addition afforded 3,4-dihydroxyphenyl-containing polybutadienes with desired catechol contents and desired molecular weights.