Highly Stereocontrolled Total Synthesis of Leukotriene B4, 20-Hydroxyleukotriene B4, Leukotriene B3, and Their Analogues

Article abstract of DOI:10.1021/jo00306a007

A highly stereocontrolled and practical new method for synthesis of LTB4 (1), 20-OH-LTB4 (2), and LTB3 (3) has been developed, which uses the palladium catalyzed coupling reaction of the vinylborane 5, derived from the C(1)-C(9) fragment 4, with the corresponding C(10)-C(20) fragments 6a-c.The acetylene 4 was synthesized by palladium-copper-catalyzed coupling reaction of (trimethylsilyl)acetylene with the bromide 12, which was prepared from γ-(trimethylsilyl)allylic alcohol (S)-10 by bromination followed by debromosilylation.The alcohol (S)-10 was obtained by the kinetic resolution of the racemate dl-10 using the Sharpless reagent.The vinyl iodides 6a and 6b were prepared from racemic γ-(trimethylsilyl)allylic alcohols dl-17 and dl-28, respectively, by the Sharpless kinetic resolution followed by the reactions taking advantage of the reactivity of vinylsilane moiety, while the segment 6c was prepared by the Sharpless kinetic resolution of racemic γ-iodoallylic alcohol dl-34 followed by protection.By using this method, precursors of the radiolabeled LTB4, and 20-OH-LTB4, i.e., 14,15-didehydro-LTB4 (40) and 14,15-didehydro-20-OH-LTB4 (41), respectively, were also synthesized.Similarly the novel structural analogue of LTB 42-44 were prepared.