Synthetic Studies on Furanosteroids: Construction of the Viridin Core Structure <i>via</i> Diels–Alder/<i>retro-</i>Diels–Alder and Vinylogous Mukaiyama Aldol-Type Reaction
作者:Evans O. Onyango、Peter A. Jacobi
DOI:10.1021/jo301232w
日期:2012.9.7
The synthesis of the viridin class of furanosteroids core skeleton from the readily available 2,3-dihydro-4-hydroxyinden-1-one (6) is described. Our strategy was broken down into three parts: (1) Synthesis of functionalized alkyne oxazoles of type 5; (2) intramolecular Diels–Alder/retro-Diels–Alder reaction of 5 followed by tautomerization and elaboration of R to give silylated furanonaphthols 4 bearing
描述了从容易获得的2,3-二氢-4-羟基茚满-1-一(6)合成呋喃丁酮类呋喃类固醇核心骨架的方法。我们的策略分为三个部分:(1)5型功能化炔恶唑的合成;(2)分子内狄尔斯-阿尔德/复古的-Diels-Alder反应5随后互变异构和R的阐述,得到甲硅烷基化furanonaphthols 4轴承醛侧链; (3)通过分子内乙烯基Mukaiyama aldol型环化环A环。最后一步面临两个主要挑战:(i)带有β-羟醛官能团(R 1 = OH)的呋喃萘酚衍生物会脱水成E- enal,在几何上不能环化,并且(ii)C17上的官能团对4到3的转化有很大影响,例如游离酮(X = O)或其衍生物(X = H,OH; X = H,OAc)环化。最后,通过类似的C17-甲酮(X = H,H)实现了成功。