Formal Total Synthesis of (+)-Lysergic Acid via Zinc(II)-Mediated Regioselective Ring-Opening Reduction of 2-Alkynyl-3-indolyloxirane
作者:Akira Iwata、Shinsuke Inuki、Shinya Oishi、Nobutaka Fujii、Hiroaki Ohno
DOI:10.1021/jo2008324
日期:2011.7.1
Asymmetric formal synthesis of (+)-lysergic acid was achieved with a reductive ring-opening reaction of chiral 2-alkynyl-3-indolyloxirane with NaBH3CN as the key step. With Zn(OTf)2 as an additive, the ring-opening reaction proceeded regioselectively at the 3-position to give the corresponding propargyl alcohol, which was a precursor of the allenic amide for palladium-catalyzed domino cyclization to
(+)-麦角酸的不对称形式合成是通过手性2-炔基-3-吲哚基环氧乙烷与NaBH 3 CN的还原步骤进行的开环还原反应完成的。以Zn(OTf)2为添加剂,开环反应在3位区域选择性进行,得到相应的炔丙醇,炔丙醇是烯丙基酰胺用于钯催化的多米诺环化反应的前体,以构建麦角生物碱核心结构。