Highly Selective Three-Step Synthesis of Rhein in Chloroaluminate Molten Salt: Preclusion of the Hayashi Rearrangement
作者:Vanessa Gonnot、Cyril Antheaume、Marc Nicolas、Charles Mioskowski、Rachid Baati
DOI:10.1002/ejoc.200900960
日期:2009.12
expeditious, three-step synthesis of rhein (2) was optimized starting from bis(N,N-diethyl)-5-methoxybenzene-1,3-dicarboxamide. The key final step, involving deprotection/cyclization of ortho-benzoylbenzoic acid 9 in acidic chloroaluminate molten salts, yielded the desired natural product with high selectivity and good overall yield by precluding the competitive Hayashi rearrangement.(© Wiley-VCH Verlag
从双 (N,N-二乙基)-5-甲氧基苯-1,3-二甲酰胺开始,优化了快速、三步合成大黄酸 (2)。关键的最后一步,包括邻苯甲酰基苯甲酸 9 在酸性氯铝酸盐熔盐中的脱保护/环化,通过排除竞争性 Hayashi 重排,以高选择性和良好的总收率获得了所需的天然产物。 (© Wiley-VCH Verlag GmbH & Co. KGaA,69451 魏因海姆,德国,2009)