Scheme 3. Synthesis of fragment 13. Reagents and conditions: (a) LiAlH₄ (0.7 eq.), THF, 0 °C, 40 min then 2-Me-C₆H₄CH₂Br (2.1 eq.), KOH (4.0 eq.), Rochelle's salt (1.2 eq.), DMF, 45 °C, 27 h, quant.; (b) n-BuLi (4.0 eq.), THF, –78 °C, 10 min to –13 °C, 90 min, 44% (over 2 steps).