Spiro indane-based phosphine–oxazoline ligands for palladium-catalyzed asymmetric arylation of cyclic N-sulfonyl imines
作者:Zhongxuan Qiu、Yanshun Li、Zhenqing Zhang、Dawei Teng
DOI:10.1007/s11243-019-00329-z
日期:2019.10
Palladium complexes of indane-based phosphine–oxazoline ligands with a spirocarbon stereogenic center were examined for asymmetric addition of arylboronic acids to cyclic N-sulfonyl imines. Excellent reaction activities (up to 99% yield) and enantioselectivities (up to 99% ee) were obtained with a broad scope of substrate.
A series of chiral phosphine‐imine ligands were synthesized starting with α‐amino acids and examined for palladium‐catalyzed asymmetric addition of arylboronic acids to cyclic N‐sulfonylimines. High catalytic activities (up to 99% yield) and high enantioselectivities (up to 98% ee) were achieved for cyclic N‐sulfonyl aldimines and ketimines with five and six‐membered ring structures.
The combination of Pd(TFA)2 and an N,N′-disulfonyl bisimidazoline ligand shows high catalytic activity and excellent asymmetric induction in the addition of arylboronic acids to cyclic N-sulfonyl ketimines including benzo[d]isothiazole-1,1-dioxides, benzo[e][1,2,3]oxathiazine-2,2-dioxides, and 1,2,5-thiadiazole-1,1-dioxides, by which three types of chiral quaternary carbon-containing sultams with substantial
Pd(TFA)2和N,N'-二磺酰基双咪唑啉配体的组合显示出高催化活性和出色的不对称诱导作用,这是因为将芳基硼酸添加到环状N-磺酰基酮亚胺中,包括苯并[ d ]异噻唑-1,1-二氧化物苯并[ e] [1,2,3]草噻嗪-2,2-二氧化物和1,2,5-噻二唑-1,1-二氧化物,可合成具有高取代多样性的三种类型的手性含季碳的均二产率高,对映选择性高(ee> 99%)。当前的催化表现出对氧气的显着耐受性,因此为构建对映体富集的环状四元立体中心提供了一种操作简单的方法。