A Convenient Synthesis of Acyclic 1,18-Diketones
【摘要】：正Acyclic diketones containing 16 methylenes are important precursors of some macrocyclic perfume compound and an useful class of compounds in view of the distinct structure feature and wide utility in medical industry, dyeing industry and organic synthesis. A number of methods have been reported so far for the synthesis of dike-tones. However, most of these methods suffer disadvantages with respect to convenience, selectivity, or efficiency and have limited applicability in preparing diketones containing less than 7 methylenes. We reported the reaction of benzimidazolium salts with Grignard reagents in which a novel synthetic method for ketones was provided. In extention of our method, the reaction of bis-benzimidazolium salts (compound 2) with Grignard reagents was studied, and a convenient synthetic method for the preparation of four 1,18-diketones was provided. The structures were confirmed by NMR, IR and MS spectra. The synthetic route is shown in Scheme 1.