Figure 2. Synthesis of novel homoisoflavanone SH-11052 (2).

Reagents and conditions: a) acetic anhydride, BF₃-OEt₂; b) 5, KOH, MeOH, 0°C, 56%; c) Pd/C, HCO₂Na, HCO₂H, 60°C, 79%; d) formalin, NaOH, 60°C, 54% for 8, 10% for 9, and 15% for 10; e) K₂CO₃, EtOH, 49% from 8, 72% from 10; f) TMSI, CHCl₃, 49%.