Chemistry of odorants: stereoselective synthesis of octahydronaphthalene-based perfumery Georgywood, (+,−)-1-[(1R∗,2S∗)-1,2,3,4,5,6,7,8-octahydro-1,2,8,8-tetramethylnaphthalen-2-yl]ethan-1-one
作者:Marco Bella、Marcello Cianflone、Gabriele Montemurro、Pietro Passacantilli、Giovanni Piancatelli
DOI:10.1016/j.tet.2004.04.007
日期:2004.5
treatment of the diastereoisomeric mixture with sodium hydride in tetrahydrofuran in the presence of an excess of methyl iodide, allowed stereoselective introduction of the methyl group at C2, leading to the formation of Georgywood in good yield (60%), as the only diastereoisomer, with a trans stereochemistry of the two methyl groups as demonstrated by NMR experiments.
描述了基于八氢萘的香料例如Georgywood的直接合成。刘易斯酸锡(IV)氯化物通过月桂烯与3-溴-丁-3-烯-2-酮的反应有效地催化了最初的一锅顺序环加成-裂解过程,从而以非常高的收率直接导致八氢萘骨架( 85%)。然后,用DBU进行脱卤化氢,得到了关键的2,4-二烯酮中间体,收率很高(85%)。通过与CH 3 Cu·BF 3(6:1的比例,70%)或(CH 3)2反应,区域选择性迈克尔加成反应形成加成产物,形成反式/顺式非对映异构体混合物。CuLi / TMSCl试剂(3:1的比例,80%)。在过量甲基碘的存在下,通过在四氢呋喃中用氢化钠处理非对映异构体混合物,生成热力学上更稳定的烯醇化物,从而允许在C2处立体选择性地引入甲基,从而以高收率形成了乔木(60% ),是唯一的非对映异构体,如NMR实验所示,具有两个甲基的反式立体化学。