Scheme 3.

Synthesis of the C1–C14 unit. Reagents and conditions: a) (−)-Ipc₂BOMe, Allylmagnesium bromide, diethyl ether, 89%; b) 19, 2,4,6-trichloro benzoylchloride, Et₃N, DMAP, 88%, 1:1 diastereomers; c) 2^nd generation Hoveyda-Grubbs catalyst, 49%, 3:2 diastereomers; d) i. PPTS, MeOH, 80 °C, 66%; ii. Et₃N, Ac₂O, DMAP, quant; e) i. DDQ, CH₂Cl₂, 70%; ii. Dess-Martin periodinane, CH₂Cl₂, 95%.