Introduction of Adjacent Oxygen-Functionalities in Dimethyl Heptalenedicarboxylates
作者:Frank Rogano、Danijela Stojnic、Anthony Linden、Khaled Abou-Hadeed、Hans-Jürgen Hansen
DOI:10.1002/hlca.201100150
日期:2011.7
the latter can be transformed into a benzyl or methyl ether group by treatment with MeONa in DMF, followed by the addition of benzyl bromide or methyl iodide (cf. Scheme 9). Reduction of the ester groups of dimethyl 7,8‐dimethoxy‐5,6,10‐trimethylheptalene‐1,2‐dicarboxylate (25′) with diisobutylaluminium hydride (DIBAH) in tetrahydrofuran (THF) leads to the formation of the corresponding dimethanol 26′
在N,N-二甲基甲酰胺(DMF)中用N-溴琥珀酰亚胺(NBS)溴化8‐甲氧基-1,6,10-三甲基庚二烯-4,5-二羧酸二甲酯(6 ;方案2)9-溴庚二烯二羧酸盐10(表1)。的醚裂解6与三甲基氯硅烷(ME 3的SiCl)/碘化钠导致oxoheptalenedicarboxylate形成13以良好的收率(方案4)。后者可以用苯中的Pb(OAc)4乙酰氧基化为(乙酰氧基)氧庚二烯二羧酸酯14(方案5)。氧代衍生物14可以依次在丙酮中用硫酸二甲酯(DMS)选择性地O-甲基化成(乙酰氧基)甲氧基庚二烯二羧酸酯15和15'(方案6)。后者的AcO基团可以通过在DMF中用MeONa处理,然后加入苄基溴或甲基碘的方法转化为苄基或甲基醚基(参见方案9)。在四氢呋喃(THF)中用氢化二异丁基铝(DIBAH)还原7,8-二甲氧基-5,6,10-三甲基庚二烯-1,2-二羧酸二甲酯(25')的酯基导致形成相应的二甲醇26