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.