Agostic interactions are often used to activate inert C–H bonds, and thus facilitate new reactions. We report the first example of designed catalysts based on the agostic interaction. Novel copper(I) complexes [BBN(pzx)2]Cu(PPh3)n (BBN = 9-borabicyclo[3.3.1]nonane; pzx = 3-substituted pyrazole; x = H, n = 2; x = Me, n = 1) and [BBN(pziPr)2]Cu}2 have been synthesized and characterized. Single crystal
激烈的相互作用经常被用来激活惰性的CH键,从而促进新的反应。我们报告了基于不良相互作用的设计催化剂的第一个例子。新型
铜(I)配合物[BBN(pz x)2 ] Cu(PPh 3)n(BBN = 9-
硼环[3.3.1]
壬烷; pz x = 3-取代的
吡唑; x = H,n = 2; x = Me,n = 1)和[BBN(pz iPr)2 ] Cu} 2已经合成和表征。对这三种化合物的单晶研究表明,分子内的C–H⋯Cu相互作用较弱,可以将其归为不良或无反应的相互作用。这些复合物对类
胡萝卜素插入NH键的催化研究表明,这些弱相互作用充当“开关”,如果与底物相互作用,则将“打开”,如果消除产物并再生弱相互作用,则将“关闭”。发现与催化作用有关的“开关”“打开”或“关闭”的过程受空间效应和溶剂的影响:非配位苯中较少空间位阻的催化剂会导致高产率,而在THF配位中受更大空间位阻的催化剂则导致相对较低的产率。