Synthesis and stereochemical assignment of brasilibactin A.

[structure: see text] Brasilibactin A, a naturally occurring siderophore related to the mycobactins, has been synthesized in six steps. Use of asymmetric titanium-mediated aldol reactions allowed the preparation of both diastereomers from a common synthetic intermediate, thus allowing the relative stereochemistry of the natural product to be assigned. Brasilibactin A exhibits no inhibition of histone deacetylases (HDACs) in spite of the N-formyl-N-hydroxy lysine moiety that is expected to affect the activity of these metal-dependent lysine-modifying enzymes.