Relative stereochemical determination and synthesis of the C1-C17 fragment of a new natural polyketide.

The challenging determination of the relative stereochemistry of a complex natural polyketide portion was achieved. After careful NMR analysis, a concise synthesis of a set of possible relative diastereomers (only 6 diastereomers out of the 32 initially envisioned) has been carried out using a common strategy based on enantioselective aldol reactions. With a high predictability, final NMR comparison established the relative stereochemistry of the C1-C17 fragment of this natural product.