[3,3]-Sigmatropic Rearrangement Step in the Gold-Catalyzed Cyclization of Allyl-(<i>ortho</i>-alkinylphenyl)methyl Ethers
作者:Martin Ackermann、Janina Bucher、Melissa Rappold、Katharina Graf、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/asia.201300324
日期:2013.8
allyl‐(ortho‐alkynylphenyl)methyl ethers was investigated, and allylated isochromenes were obtained. An optimization of the catalysis conditions with respect to different phosphane and carbene ligands on gold, different counterions, and different solvents was conducted. Subsequently, the scope and limitations of this reaction were investigated with 21 substrates. The mechanistic studies show an allylic inversion
烯丙基(邻位)的金催化转化研究了炔基苯基)甲基醚,获得了烯丙基化异色酮。针对金,不同抗衡离子和不同溶剂上的不同膦和卡宾配体的催化条件进行了优化。随后,用21种底物研究了该反应的范围和局限性。机理研究表明,NMR数据和X射线晶体结构分析以及通过交叉实验确定的分子间反应均支持烯丙基反转。即使在有水的情况下,也没有原型脱脂的竞争。所有这些观察从其它相关的转换不同,并且清楚地表明由[3,3]产物形成σ重排在步骤形成新的C C键。