在Mukaiyama aldol反应中,使用了一系列基于阳离子单齿和双齿碘(苯)咪唑鎓的卤素键(XB)供体。尽管5摩尔%的单齿变体显示出显着的活性,但顺式预组织的双齿XB供体即使在0.5摩尔%的负载下也具有很强的性能。与非常活泼的BAr F 4盐相反,PF 6或OTf盐要么不活泼,要么通过路易斯碱催化显示出背景反应。重复实验清楚地排除了元素碘潜在的隐藏催化作用,并证明了我们的催化剂在三个连续循环中的稳定性。
Homogeneous catalysis. A transition metal based catalyst for the Mukaiyama crossed-aldol reaction and catalyst deactivation by electron transfer.
作者:William Odenkirk、John Whelan、B. Bosnich
DOI:10.1016/0040-4039(92)89017-7
日期:1992.9
The cationic complex [Ru(salen)(NO)H2O]SbF6 is intrinsically a powerful catalyst for the Mukaiyama crossed-aldol reaction at 25°C in nitromethane solutions and at very low catalyst loadings but, for some reactions, electron transferfrom the silylenolether to the ruthenium catalyst can occur which leads to catalyst deactivation.