Figure 2. Scheme for the synthesis of turkesterone 11-acyl derivatives: i) phenylboronic acid, dry DMF, r.t. 2 h, ii) addition of dry DMP, dry acetone and fused p-TsOH, r.t. 3h, iii) R-COOCO-R, dry pyridine (or pyridine/benzene 6:5 v/v), r.t. (or 50°C) for 2-20 h and iv) 0.1M HCl/dioxan (1:1 v/v), r.t. 4 h.