Stereodefined synthesis of the four possible stereoisomers of 5,18-diHETE

A Stereocontrolled Total Synthesis of Lipoxin B4 and its Biological Activity as a Pro‐Resolving Lipid Mediator of Neuroinflammation

“…The first route to dienyne 4 depended on a Wittig olefination between phosphonium salt 6 and aldehyde 7 , itself the product of a Wittig one‐carbon homologation/isomerization cascade on epoxy aldehyde 11 . We initially elected to define the stereochemistry of the vicinal diol moiety via asymmetric carbonyl reduction and Sharpless asymmetric epoxidation process, [16] and constructed 11 from hexanoyl chloride 12 using an approach similar to that taken by Kobayashi and co‐workers in their syntheses of hydroxyeicosatetraenoic acids (HETEs) [17] and resolvins [18,19] . An alternative route to dienyne 4 depended on the Horner‐Wadsworth‐Emmons (HWE) reaction of phosphonate 9 with aldehyde 8 ; similar olefinations have been used in the syntheses of various other triene and tetraene natural products and derivatives [20a–g] .…”

Stereoselective Construction of (E,Z)‐1,3‐Dienes and Its Application in Natural Product Synthesis

“…The synthesis of polyunsaturated fatty acid derivatives was also accomplished by taking advantage of Wittig olefinations to install the E,Z-diene moieties that are common in compounds of this type. [114][115][116][117][118] As an example, the synthesis of primary alcohol 136, a key intermediate for preparing (14S,21R)-dihydroxy docosahexaenoic acid (diHDHA), is depicted in Scheme 53. [115] A target that inspired the use of Wittig and related olefination reactions is (À )-callystatin A (Scheme 54).…”