Chemoenzymatic Synthesis of the C3–C11-Fragment of Borrelidin


  • Dedicated to Professor Dieter Jahn on the occasion of his 60th birthday


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 monooxygenase CYP102A1 as biocatalyst. The fourthstereocenter in the C3–C11 fragment was generated by chiral auxiliary mediated alkylation. In order to explain the experimental results of the alternative epimerization of an all-syn polypropionate, quantum chemical calculations were performed at the B3LYP/cc-pVDZ level.