作者:Marc Renom-Carrasco、Piotr Gajewski、Luca Pignataro、Johannes G. de Vries、Umberto Piarulli、Cesare Gennari、Laurent Lefort
DOI:10.1002/chem.201601501
日期:2016.7.4
equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N‐benzylated 3‐substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3N, a Rh‐JosiPhos catalyst reduced a range of pyridinium salts with ee values up to 90 %. The role of the base was elucidated with a mechanistic study involving the isolation of the various reaction
在N-苄基化3-取代的吡啶鎓盐不对称加氢成相应的哌啶中,使用等量的有机碱会导致高对映体过量。实际上,在存在Et 3 N的情况下,Rh‐JosiPhos催化剂可还原一系列ee值高达90%的吡啶鎓盐。通过涉及各种反应中间体的分离和同位素标记实验的机理研究阐明了该碱的作用。另外,该研究为涉及二氢吡啶中间体的对映体确定步骤提供了一些证据。