2-Substituted 1,3-benzoxathiolium tetrafluoroborates were used as efficient masked acylating agents for N,N-dialkylarylamines in a two-step reaction. In most of the cases intermediate 2,2-disubstituted 1,3-benzoxathioles were obtained in high yields (about 90%) and their hydrolysis afforded the corresponding ketones in almost quantitative yields. The new procedure offers the following advantages: (1) the reaction conditions are mild; (2) the acylation proceeds selectively at the para-position as referred to the dialkylamino group; (3) the introduction of a tertiary group is easily accomplished.
在一个两步反应中,2-取代的 1,3-
苯并噁
硫鎓四
氟硼酸盐被用作
N,N-二烷基芳基胺的高效掩蔽酰化剂。在大多数情况下,
2,2-二取代的 1,3-
苯并噁
硫醇
中间体都能以高产率(约 90%)获得,
水解后几乎能得到定量的相应
酮。新方法具有以下优点:(1)反应条件温和;(2)酰化选择性地在对位进行,而不是在二烷基
氨基上进行;(3)很容易引入三级基团。