Structure of reactive aggregate of lithium reagents and its application to the generation of highly-activated reagents.

有机锂是合成化学中最常用的试剂之一。为了更好地了解它们的反应性和反应机理，有必要对反应性有机锂试剂的结构进行阐明。通过低温核磁共振波谱分析发现，在甲苯中等摩尔混合物中形成了锂酯烯醇酯-手性二醚-锂二异丙酰胺三元配合物。该配合物在不对称迈克尔反应中表现出较高的反应活性和对映选择性。

Organolithiums are one of the most frequently-used reagents in synthetic chemistry. To better understand their reactivity and reaction mechanisms, it is necessary to elucidate the structure of reactive organolithium reagents. We found that a ternary complex reagent of lithium ester enolate-chiral diether-lithium diisopropylamide was formed in an equimolar mixture of these reagents in toluene based on low-temperature NMR spectroscopy. This complex shows high reactivity and enantioselectivity in an asymmetric Michael reaction.