3S)-epoxy butanoate 8 followed by methylation gave the tetrahydro-2-furylidene acetate (−)-9, which was converted to the left-half aldehyde (+)-4. A Wittig reaction between (+)-4 and the phosphoranylide derived from the bithiazole-type phosphonium iodide 5 using lithium bis(trimethylsilyl)amide afforded the (+)-cystothiazole A (2).
由(2 R,3 S)-环氧
丁酸酯8衍生的(2 R,3 S)-3-甲基戊4炔-1,2
-二醇(7)的
钯催化环化-甲氧基羰基化,然后甲基化得到四氢
乙酸-2-亚
呋喃酯(-)- 9,将其转化为左半醛(+)- 4。使用双(三甲基甲
硅烷基)酰胺
锂,(+)- 4与衍生自苄基唑型
碘化5 5的
磷酰内酯之间的维蒂希反应,得到(+)-巯基
噻唑A(2)。