Enantiospecific and Stereospecific Synthesis of Lipoxin A. Stereochemical Assignment of the Natural Lipoxin A and Its Possible Biosynthesis

Article abstract of DOI:10.1021/ja00288a032

Both chemical and enzymatic steps were employed to convert leukotriene A₄ and its unnatural epoxide isomers into four diastereomeric 5(S),6(S),15(S)-trihydroxy-7,9,13-trans-11-cis-eicosatetraenoic acids, possible structures for lipoxin A.These compounds were correlated with trihydroxy tetraene eicosatetraenoic acids derived from tetraene epoxide 3, and the relative stereochemistries of the 5 and 6 positions were assigned.These assignments were confirmed by total synthesis of two diastereomers of lipoxin A.One of these isomers, 5(S),6(S),15(S)-trihydroxy-7-9,13-trans-11-cis-eicosatetraenoic acid (1b), corresponded to lipoxin A derived from natural sources.The structure and possible biosyntheses of lipoxin A are proposed.