The ex-chiral pool synthesis of the Theodorakis C3-C11 fragment of borrelidin (1) by a chemoenzymatic approach in nine steps and 12 % overall yield starting from enantiopure methyl-branched preen gland wax esters is described. In the initial reaction, the wax ester was (ω-1)-hydroxylated regioselectively by using a mutant of the cytochrome P450

The construction of novel borrelidin analogues is reported in which the northern fragment is truncated to a simple hydroxyundecanecarboxylate and the original cyclopentanecarboxylic acid in the southern fragment is replaced with different six-membered rings. The required precursors were prepared by cross metathesis of the appropriate carbocycle-based homoallylic alcohol with crotonaldehyde followed by HWE olefination of the resulting enal with bromocyanophosphonate. The key aldehyde for intramolecular cross coupling was accessible by oxidation of the hydroxy group of the linked undecanecarboxylate unit. Grignard mediated macrocyclization finally yielded the borrelidin related products. The investigation is complemented by SAR studies and quantum-chemical calculations.