First total synthesis of Combretastatin D-2 congeners named Isocorniculatolide A and 11-o-methylisocornicultolide

ABSTRACT

First total synthesis of newly isolated natural products Isocorniculatolide A and 11-o-methylisocornicultolide A was accomplished. Commercially available 3, 4 dihydroxy benzaldehyde was selectively protected at the 4- position followed by the Wittig elongation to afford α, β unsaturated ester which was subsequently treated with DIBAL to afford (E)-2-(benzyloxy)-5-(3-hydroxyprop-1-enyl) phenol and then finally coupled this intermediate with 3-(4-bromophenyl) propanoic acid to achieve (Z)-3-(4-(benzyloxy)-3-hydroxyphenyl) allyl 3-(4-bromophenyl) propanoate. Finally macro cyclization using Ullmann ether synthesis and then treatment with Pd/C accomplished Isocorculatolide A. In the same way we achieved 11-o-methylisocornicultolide starting from Isovanillin.