Atropisomeric [(diphosphine)Au<sub>2</sub>Cl<sub>2</sub>] Complexes and their Catalytic Activity Towards Asymmetric Cycloisomerisation of 1,6-Enynes
作者:Elena M. Barreiro、Ekaterina V. Boltukhina、Andrew J. P. White、King Kuok Mimi Hii
DOI:10.1002/chem.201404496
日期:2015.2.2
appear to be very dependent upon the phosphorous substituent. Conversely, the same effect was not observed for ligands based on the binaphthyl (BINAP) series. The catalytic activity of these complexes was subsequently assessed in the enantioselective cycloisomerisation of 1,6‐enynes and revealed an over‐riding electronic effect: more‐electron‐rich phosphines promote greater enantioselectivity. The possibility
两个[(二膦)Au 2 Cl 2的X射线晶体结构]配合物(其中二膦= P-Phos和二甲苯基-P-Phos; P-Phos = [2,2',6,6'-四甲氧基-4,4'-双(二苯基膦基)-3,3'-联吡啶])进行测定,并与类似的阻转异构金配合物的报道结构进行比较。配体的联芳基系列(MeOBIPHEP,SEGPhos和P-Phos; BIPHEP = 2,2'-双(二苯基膦基)-1,1'-联苯,SEGPhos = [Au⋅⋅⋅Au距离与扭转角之间的相关性可以制备(4,4'-bi-1,3-苯并二恶唑)-5,5'-二基]双[二苯基膦]);这些测量结果似乎非常依赖于磷取代基。相反,对于基于双萘基(BINAP)系列的配体,未观察到相同的效果。随后在1,6-烯炔的对映选择性环异构化中评估了这些配合物的催化活性,并显示了压倒性的电子效应:电子含量更高的膦可促进更大的对映选择性。在这些反应中排除了银充当(助)催化剂的可能性。