Magnesium Halide-promoted Ring-opening Reaction of Cyclic Ether in the Presence of Phosphine Halide
作者:Yu-Chang Chang、Chia-Ming Weng、Tanveer M. Shaikh、Fung-E Hong
DOI:10.1002/jccs.201500154
日期:2015.8
preparation of H‐phosphinate esters has been explored. The ring‐opening reaction of cyclic ether (tetrahydrofuran or tetrahydropyrane) was carried out with magnesium halide in the presence of phosphine halide (PRCl2 or PCl3). The process is straightforward and all the reagents are relatively cheap and readily available. Magnesium halide‐mediated THF ring‐opening (SN2@C) and the subsequent SN2@P elementary
探索了直接制备H-次膦酸酯的新途径。环醚(四氢呋喃或四氢吡喃)的开环反应是在卤化膦(PRCl 2或PCl 3)存在下与卤化镁进行的。该过程简单明了,所有试剂相对便宜并且容易获得。卤化镁介导的THF开环(S Ñ 2 @ C)和随后的小号Ñ @表示P基本反应,其引起所述中间卤代烷基次膦酸盐已根据我们的实验结果进行了讨论(2路径I:S Ñ 2 @ C + S N 2 @ P)。另一种可能的路线,直接S NTHF(亲核体)和膦卤化物(电体),其接着通过从卤化物膦卤化物解离THF开环之间2(路径II:小号Ñ 2 @ P- + S Ñ 2 @ C),还有人提议。但是,路径II是最不可能的反应路径,因为中性THF并不是良好的亲核试剂。H-次膦酸酯很容易在随后的水解过程中获得。考虑到卤化镁中的离子键强度以及在质子溶剂(例如水)中从MgX 2解离的卤化物的亲核性,建议将MgBr 2用于环状醚的开环反应。