Synthesis of the C10–C17 fragment of aurisides and callipeltosides

The key unsaturated chiral C10–C17 fragment common on the synthesis of aurisides and callipeltosides was synthesized in six steps from 5-bromopentadienal via aldol condensation with Nagaoʹs chiral auxiliary and further manipulation using Ohiraʹs reagent and Negishiʹs carboalumination–iodination.