AbstractTo expand the chemical space of chiral N‐oxides and chiral furan‐containing ligands, herein we designed and synthesized a new class of rigid‐featured tertiary amine‐derived C2‐symmetric chiral furan‐N,N′‐dioxide (Fu‐2NO) ligands from optically pure l‐prolinamides/hydroxylprolinamides in operationally simple two steps and up to 57 % overall yield. The newly developed rigid‐featured chiral Fu‐2NO ligands possesses two pyrroloimidazolone‐based N‐oxides as non‐flat chiral walls, and afforded the opportunity for fine‐tuning the ligand electronic and conformational properties by judicious choice of the substituent in the nonligating nitrogen atom. More importantly, The Fu‐2NO ligands can tolerate air and moisture such that no special handling is needed for their storage, and can be applied in the Ni(II)‐catalyzed asymmetric Friedel‐Crafts alkylation reaction of indole.
摘要 为了拓展手性 N-氧化物和含手性呋喃配体的化学空间,我们在本文中以光学纯的 l-脯氨酰胺/羟基脯氨酰胺为原料,设计并合成了一类新的刚性特征叔胺衍生 C2 对称手性呋喃-N,N′-二氧化物(Fu-2NO)配体,只需简单的两步操作,总产率高达 57%。新开发的刚性手性 Fu-2NO 配体具有两个吡咯咪唑酮基 N-氧化物作为非平面手性壁,并提供了通过明智选择非配位氮原子上的取代基来微调配体电子和构象特性的机会。更重要的是,Fu-2NO 配体能够耐受空气和湿气,因此在储存时无需特殊处理,并可用于 Ni(II) 催化的吲哚不对称 Friedel-Crafts 烷基化反应。