Skip to main content
. Author manuscript; available in PMC: 2013 Jul 1.
Published in final edited form as: European J Org Chem. 2012 Jun 13;2012(22):4130–4139. doi: 10.1002/ejoc.201200286

Scheme 4.

Scheme 4

Synthesis of polyene fragment 3. Reagents and conditions: a) Zn (10 equiv.), acrolein (1.0 equiv.), THF, reflux, 2 h, 84% based on effective starting material; b) DIBAL-H (1.0 equiv.), CH2Cl2, −78 °C, 2 h; c) Ph3P=CHCOOEt (1.3 equiv.), toluene, 100 °C, 16 h, 33% two steps; d) 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.3 equiv.), (+)-CSA (10 mol %), 4 Å MS, CH2Cl2, 0 °C to 23 °C, 24 h, 80%; e) NaOH (3.0 equiv.), EtOH/H2O, 0 °C to 23 °C, 12 h, 77%. DIBAL-H = diisobutyl aluminium hydride, CSA = camphor sulfonic acid.