1. According to the general procedure, 4-bromobenzaldehyde (277 mg) was used. The crude product was purified with EtOAc / CH 2 Cl 2 = 2:98 to afford 2e (279 mg, 58%) as a yellow solid;Mp 201?203 �C; anal. calcd. for C 27 H 29 BrO 3 C, 67.36; H, 6.07; found C, 67.24; H, 5.99; 1 H NMR (500 MHz, CDCl 3 ): ? H 0.81 (s, 3H, 18-H 3