Direct conversion of cinnamate esters into β,β-disubstituted ketones mediated by cyano-magnesio cuprates
作者:Douglas T. Genna、Gary H. Posner
DOI:10.1016/j.tet.2016.05.003
日期:2016.10
clean synthesis of unsymmetrical ketones from carboxylic acid derivatives has been a challenge in the organic community dating back over 80 years. Herein we report the conversion of simple alkyl cinnamates to β,β-disubstituted ketones with cyano-magnesio cuprates in high yields with no observation of tertiary alcohol byproduct. The lack of tertiary alcohol is attributed to a putative enolate intermediate
由羧酸衍生物清洁合成不对称酮一直是80年前有机界的一个挑战。在本文中,我们报道了氰基-镁铜酸盐以高收率将简单的烷基肉桂酸酯转化为β,β-二取代的酮,没有观察到叔醇副产物。叔醇的缺乏归因于作为酮保护基的推定的烯醇酸酯中间体。观察到明显的空间抑制趋势与母体酯上的R基团的大小和亲核的铜酸盐有关。最后,我们证明了该反应可以与已知的铜介导的烯丙基取代反应偶联,从而从母体α-氯-β,γ-乙烯酯(7)产生β,γ-二取代的酮(8)。