Synthesis of Rosavin and its analogues based on a Mizoroki-Heck type reaction

The Rosavin framework could be constructed with either phenylboronic acids, the protected arabinopyranosyl bromide 4 or the protected xylopyranosyl bromide 5 , along with allyl O -β- d -glucopyranoside 7 that could be easily prepared based on direct β-glucosidation between allyl alcohol and d -glucose using the immobilized β-glucosidase (EC 3.2.1.21). The key reaction was the Pd(II)-catalyzed Mizoroki-Heck type reaction between allyl β- d -glucopyranoside congeners 9 or 10 and arylboronic acids. Deprotection of the coupling products afforded synthetic Rosavin 1 , 4-methoxycinnamyl 6- O -(α- l -arabinopyranosyl)-β- d -glucopyranoside 2 , and cinnamyl 6- O -(β- d -xylopyranosyl)-β- d -glucopyranoside 3 , which were identical with the natural products in respect to the specific rotation and spectral data.