Biomimetic synthesis of acid-sensitive (−)- and (+)-caparrapi oxides, (−)- and (+)-8-epicaparrapi oxides, and (+)-dysifragin induced by artificial cyclases
作者:Muhammet Uyanik、Kazuaki Ishihara、Hisashi Yamamoto
DOI:10.1016/j.bmc.2005.04.029
日期:2005.9
Asymmetric total syntheses of acid-sensitive (-)- and (+)-caparrapi oxides (1) and (+)-8-epicaparrapi oxide (2) from farnesol (10) are achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Bronsted acid (chiral LBA)-induced polyene cyclization as key steps. The relative configuration of (+)-dysifragin (4) is determined by a single-crystal X-ray diffraction and its total synthesis is accomplished
使用Sharpless-Katsuki环氧化和Lewis酸辅助可实现法呢醇(10)对酸敏感性(-)-和(+)-caparrapi氧化物(1)和(+)-8-epicaparrapi氧化物(2)的不对称总合成。手性布朗斯台德酸(手性LBA)诱导多烯环化是关键步骤。(+)-dysifragin(4)的相对构型由单晶X射线衍射确定,其总合成由(+)-1的非对映选择性环氧化完成。此外,可以通过克服了底物控制的试剂控制从具有88%ds的(S)-神经节醇(3)和(R)-LBA直接合成(-)-1,而从(R)获得(-)-2 )-3和(R)-LBA的双不对称诱导具有> 99%ds。