The total synthesis of six naturally occuring enantiomerically pure oxygen containing mycolic acids was achieved. The specific mycolic acids synthesized were cis-cyclopropane methoxy-mycolic acid (I) and a-methyl trans-cyclopropane methoxy-mycolic acid (II) of Mycobacterium tuberculosis; and the protected S-a- methyl trans-alkene keto-mycolic acid (III), R-a-methyl trans-alkene keto-mycolic acid (IV), R, R a-methyl trans-alkene hydroxy-mycolic acid (V) and S, S a-methyl trans-alkene hydroxy-mycolic acid (VI) of Mycobacterium marinum. Novel routes in the preparation of the first synthetic a-methyl trans-alkene mycolic acids are discussed, utilising methods such as the modified Julia-Kocienski olefination, the Horner-Wadsworth-Emmons reaction and the Michael addition.