General procedure B for the saponification of esters. To a solution of the ester (1 mmol) in MeOH (20 mL) was added 10 mL of an aq. NaOH solution (2.0 M). The reaction was stirred at room temperature, and the progress of the reaction was monitored by TLC. After full conversion (2-3 h), the volume was reduced in vacuo, and the mixture was cooled, gently acidified with 2 N HCl, and extracted with EtOAc (3 × 15 mL). The combined organic phases were dried over Na2SO4, filtered, and removed under reduced pressure. The product was used for the next step without further purification.