Catalytic asymmetric heterogeneous aziridination of styrene derivatives using bis(oxazoline)-modified Cu2+-exchanged zeolite Y
作者:Darragh Ryan、Paul McMorn、Donald Bethell、Graham Hutchings
DOI:10.1039/b411040b
日期:——
higher than that for the equivalent homogeneously catalysed reaction. With copper-exchanged zeolite Y the leaching of Cu2+ into solution during reaction was much lower for the substituted styrene derivatives (0.4-7% of total Cu) than with styrene itself (10.3% of the total Cu). The effect of reaction time on aziridine yield reveals an S-shaped profile that is accentuated by the position of the substituent
使用[N-(对-硝基苯基磺酰基)亚氨基]苯基碘丁烷(PhI =描述和讨论了作为氮供体的NNs。对于均相催化的反应,尽管4-氯苯乙烯确实提供了增强的ee,但与苯乙烯相比,几乎所有取代的衍生物都具有较低的ee,但其氮丙啶的产率较低。对于非均相催化反应,苯乙烯衍生物通常具有提高的产率,特别是当取代基在4-位时。对于2-氯苯乙烯(95%)和4-氯苯乙烯(94%)观察到特别高的ee,并且通常观察到与2-和4-取代的衍生物进行多相催化反应的ee明显高于均等的ee。催化反应。用铜交换沸石Y,在反应过程中,取代的苯乙烯衍生物的Cu 2+浸出到溶液中的比例(占总Cu的0.4-7%)要比苯乙烯本身(占总Cu的10.3%)低得多。反应时间对氮丙啶产率的影响揭示了一个S形的轮廓,该轮廓被取代基的位置所加重,并且在均相催化的途径和非均相催化的反应中均观察到该效应。一系列竞争性实验,其中苯乙烯与当量的2-进行共反应,