Mild N-deacylation of secondary amides by alkylation with organocerium reagents

Secondary amides are a class of highly stable compounds serving as versatile starting materials,intermediates and directing groups（amido groups） in organic synthesis.The direct deacylation of secondary amides to release amines is an important transformation in organic synthesis.Here,we report a protocol for the deacylation of secondary amides and isolation of amines.The method is based on the activation of amides with Tf_2O.followed by addition of organocerium reagents,and acidic work-up.The reaction proceeded under mild conditions and afforded the corresponding amines,isolated as their hydrochloride salts,in good yields.In combination with the C-H activation functionalization methodology,the method is applicable to the functionalization of aniline as well as conversion of carboxylic derivatives to functionalized ketones.

仲酰胺经酰胺活化直接合成酮的普适性方法

本文报道仲酰胺经去胺基烷基化反应直接合成酮的通用性方法.这一新的C—C键形成方法是基于Tf2O对仲酰胺的活化及有机铈试剂对活化所形成活性中间体的加成而实现的.该方法可用于各种酮的合成,包括烷基-烷基酮、烷基-芳基酮、芳基-芳基酮、α,β-不饱和酮以及β-氯-α,β-不饱和酮等,收率65%～90%.研究表明,除了有机铈试剂外,碱性较弱的炔基硼试剂、温和亲核性的烯丙基三甲基硅烷以及低亲核性的苯乙烯均可与仲酰胺的活化中间体进行加成反应,水解后生成相应的酮.因此,该方法具有较好的普适性和重要的合成应用价值.基于实验结果和验证实验,提出经由腈鎓中间体的可能反应机理.本法使仲酰胺成为形式上的酰化试剂,不但可与有机金属试剂反应,还可与烯丙基三甲基硅烷和苯乙烯进行还原酰化反应.