An Alternative Access to (�)-?-Irones and (�)-?-Ironevia Acid-Mediated Cyclisation
作者:Karl H. Schulte-Elte、Herv� Pamingle、Arnold P. Uijttewaal、Roger L. Snowden
DOI:10.1002/hlca.19920750312
日期:1992.5.6
Acid-mediated cyclisation of trienone 8, readily available from 2,3-dimethylbutanal (1; five steps: 47% yield), using fluorosulfonic acid (6.8 mol-equiv.) in 2-nitropropane at −70°, afforded a 14:9:1 mixture (70% yield) of (±)-cis-α-irone (9), (±)-trans-α-irone (10), and (±)-β-irone (11). Other acidic conditions examined, using 95% aq. H2SO4 solution, 85% aq. H3PO4 solution, or SnCl4, gave inferior
酸介导的三烯酮8的环化反应可容易地从2,3-二甲基丁醛(1步;五个步骤:47%收率),使用氟磺酸(6.8摩尔当量)在2-硝基丙烷中于-70°加热得到14: (±)-顺式-α-酮(9),(±)-反式-α-酮(10)和(±)-β-酮(11)的9∶1混合物(70%产率)。使用95%aq。H 2 SO 4溶液,水溶液85%。H 3 PO 4溶液或SnCl 4给出的结果较差。
Kron A. A., Fedotowa S. M., Nowikow N. A., Zh. organ. khimii, 30 (1994) N 4, S 500-502