Fungal sphingolipid synthesis

Kobayashi has reported a remarkable series of chiral Zr(IV) complexes as catalysts for enantioselective aldol addition reactions [136, 137]. These are readily prepared from 3,3 -dihalo-BINOL derivatives and Zr(OtBu)4. The putative zirconium complex 266 is reported to mediate the formation of anti aldol adducts with excellent diastereo- and enantioselectivity (Scheme 4.33). It is noteworthy that under optimal conditions, the reactions are carried out in aqueous propanol/toluene solvent mixtures. As such, the process is tolerant of and indeed thrives in, the presence of water. A demonstration of its use was reported in the synthesis of khafrefungin (269), an inhibitor of fungal sphingolipid synthesis [137]. 

Kobayashi, S. Mori, K. Wakabayashi, T Yasuda, S. Hanada, K. 2001. Convergent total synthesis of khafrefungin and its inhibitory activity of fungal sphingolipid syntheses. J. Org. Chem. 66 5580-5584. 

In summary, fungal cells are believed to construct two different pools of ceramides to be used for the synthesis of different sphingolipids... 

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