Scheme 2.

Synthesis of Allyl Derivative 19^a

^aReagents and conditions: (a) H₂C=CHCH₂NH₂, MgSO₄, CHCl₃, room temperature, overnight (99%); (b) 9, CHCl₃, room temperature, 18 h (26%); (c) SOCl₂, CH₃OH, 0 °C to room temperature, 6 h; (d) (1) NaHMDS, THF, then PhSeCl, −78 °C to room temperature, overnight, (2) H₂O₂, CH₃CO₂H, 0 °C to room temperature, overnight; (e) KOH, water/ethylene glycol (1:3), reflux, 12 h (43% over three steps).