Centre for Synthesis and Chemical Biology, School of Chemistry, The University of Dublin, Trinity College, Dublin 2, Ireland.
J Org Chem. 2011 Jan 21;76(2):347-57. doi: 10.1021/jo101791w. Epub 2010 Oct 27.
It has been shown for the first time that triazolium precatalysts promote (in the presence of base) highly chemoselective crossed acyloin condensation reactions between aliphatic and ortho-substituted aromatic aldehydes. An o-bromine atom can serve as a temporary directing group to ensure high chemoselectivity (regardless of the nature of the other substituents on the aromatic ring) which then can be conveniently removed. The process is of broad scope and is operationally simple as it does not require the preactivation of any of the coupling partners to ensure selectivity. Preliminary data indicate that highly enantioselective variants of the reaction are feasible using chiral precatalysts.
这是首次表明三唑鎓前催化剂在碱的存在下促进高度选择性的脂肪族和邻位取代芳香醛之间的交叉丙二醛缩合反应。邻溴原子可以作为临时导向基团，以确保高化学选择性（与芳环上的其他取代基的性质无关），然后可以方便地去除。该过程具有广泛的应用范围，并且操作简单，因为它不需要对任何偶联物进行预激活以确保选择性。初步数据表明，使用手性前催化剂可以实现反应的高度对映选择性变体。
