Base catalysed rearrangements involving ylide intermediates. Part 2. The Stevens [1,2] and [3,2] sigmatropic rearrangements of allylic ammonium ylides
作者:Robert W. Jemison、Trevor Laird、W. David Ollis、Ian O. Sutherland
DOI:10.1039/p19800001450
日期:——
The base catalysed rearrangement of the quaternary ammonium salts (9) usually gives the [3,2] sigmatropic rearrangement product (10) rather than the Stevens [1,2] rearrangement product (11). An earlier claim has been corrected : the corresponding reaction of the acetylenic ammonium chloride (16) gives the allene (18). These results are discussed in terms of a competition between the symmetry-allowed
季铵盐(9)的碱催化重排通常产生[3,2]σ重排产物(10),而不是Stevens [1,2]重排产物(11)。先前的一项主张已得到纠正:炔属氯化铵(16)的相应反应生成了丙二烯(18)。根据对称性允许的[3,2]σ重排与非允许的Stevens [1,2]重排之间的竞争来讨论这些结果,该竞争被表述为通过自由基对中间进行或作为协调对称-禁止的过程。