Synthesis and absolute structure of manzacidin B.

[reaction: see text] Four possible stereoisomers of manzacidin B were synthesized using stereochemically defined synthetic routes via the azide 7 and oxazoline 11 starting with the (R)-alpha-methyl Garner aldehyde 5. Comparisons of the spectroscopic data of the synthetic isomers 4a-d with those of the natural manzacidin B revised the proposed structure 3 to (4S,5S,6R)-4d.