CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP44099, 31077 Toulouse Cedex 4 (France) http://www.lcc-toulouse.fr/lcc/spip.php?article24; Université de Toulouse, UPS, INPT, 31077 Toulouse (France).
Angew Chem Int Ed Engl. 2014 Jun 16;53(25):6482-6. doi: 10.1002/anie.201402301. Epub 2014 May 6.
A challenging synthetic modification of PEPPSI-type palladium pre-catalysts consisting of a stepwise incorporation of one and two amino groups onto the NHC skeleton was seen to exert a sequential enhancement of the electronic donor properties. This appears to be positively correlated with the catalytic performances of the corresponding complexes in the Buchwald-Hartwig amination. This is illustrated, for example, by the quantitative amination of 4-chloroanisole by morpholine within 2 h at 25 °C with a 2 mol% catalyst/substrate ratio or by a significant reduction of catalytic loading (down to 0.005 mol%) for the coupling of aryl chlorides with anilines (max TON: 19,600).
一种具有挑战性的 PEPPSI 型钯前催化剂的合成修饰方法，包括逐步将一个和两个氨基基团引入 NHC 骨架中，这被认为可以连续增强电子给体性质。这似乎与相应配合物在 Buchwald-Hartwig 胺化反应中的催化性能呈正相关。例如，通过在 25°C 下以 2mol%的催化剂/底物比，用吗啉定量胺化 4-氯苯甲醚，或者通过显著降低芳基氯化物与苯胺偶联的催化负载量（低至 0.005mol%）（最大 TON：19600），都可以说明这一点。
