Reaction of the dimers [RuCl2(arene)]2 with pyridyloxazolines (pymox) gave complexes [RuCl(pymox)(arene)][SbF6] 1â12 which have been fully characterised. Using chiral ligands diastereomers are formed, the diastereoselectivity depending on the substituents on the arene and on the oxazoline. The complexes [RuCl(Me2-pymox)(mes)][SbF6] 1, [RuCl(Ph-pymox)(mes)][SbF6] 3, [RuCl(iPr-pymox)(mes)][SbF6] 5 and [RuCl(indanyl-pymox)(mes)][SbF6] 12 (mes = mesitylene) have been characterised by X-ray crystallography. Treatment of these cations with AgSbF6 generates dications which in some cases can be isolated as aqua species [Ru(OH2)(pymox)(arene)]2+; these dications are enantioselective catalysts for DielsâAlder reactions of acroleins and dienes; a mechanism is proposed which accounts for the observed enantioselectivity.
二聚体[RuCl2(arene)]2 与
吡啶恶唑(hypmox)反应生成了[RuCl(hypmox)(arene)][SbF6] 1â12 复合物,对这些复合物进行了全面的表征。使用手性
配体可形成非对映异构体,非对映选择性取决于炔和
噁唑啉上的取代基。复合物 [RuCl(Me2-pymox)(mes)][SbF6]1、[RuCl(Ph-pymox)(mes)][SbF6]3、[RuCl(iPr-pymox)(mes)][SbF6]5 和 [RuCl(
茚基-pymox)(mes)][SbF6]12(mes=mesitylene)已通过 X 射线晶体学进行了表征。用 AgSbF6 处理这些阳离子会产生二阳离子,在某些情况下,这些二阳离子可分离为
水合物 [Ru(OH2)(pymox)(arene)]2+;这些二阳离子是
丙烯醛和二烯的 DielsâAlder 反应的对映体选择性催化剂;提出了一种机制来解释所观察到的对映体选择性。