Side Arm Strategy for Catalyst Design: Modifying Bisoxazolines for Remote Control of Enantioselection and Related

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	Side Arm Strategy for Catalyst Design: Modifying Bisoxazolines for Remote Control of Enantioselection and Related
	Liao SH(廖赛虎)1; Sun XL(孙秀丽)1; Tang Y(唐勇)1
刊名	Accounts Chem. Res.
	2014
卷号	47 期号:8 页码:2260-2272
其他题名	边臂策略设计双恶唑啉催化剂远程控制对映选择性及其他
通讯作者	唐勇
英文摘要	CONSPECTUS: In asymmetric catalysis, the remote control of enantioselection is usually difficult due to the long distance communication between the chiral center of the catalyst and the reactive site of the substrate. The development of efficient and highly enantioselective catalysts for such reactions is of great importance and highly desirable. The stereocontrol over an asymmetric reaction is a delicate process (ca. 3.0 kcal/mol difference in transition states can lead to >99/1 enantiomeric selectivity at room temperature), it therefore requires fine-tuning on the electronic nature of the central metal together with a precisely created cavity to accommodate the substrates and reagents. We envision that a solution is the design of new catalysts by finding an easy and efficient way to tune the electronic properties, the chiral space, and the shape of the catalytic site. Since an extra coordination group in the organometallic complex could not only alter the microenvironment around the metal center in a three-dimensional manner but also tune the electronic properties of the metal center, about 10 years ago, we introduced a side arm strategy for ligand/catalyst design. This Account describes our efforts toward this goal. Based on this side arm strategy, we have developed two series of ligands based on the bisoxazoline framework; namely, trisoxazoline (TOX) ligands and side armed bisoxazoline (SaBOX). The "side arms" are shown to play multiple roles in different cases, for example, as a ligating group, a steric group, or a directing group, which are dependent on the metal and the functionality at the side arm. Metal catalysts based on these ligands have proven to be highly efficient for a number of asymmetric transformations, including Friedel Crafts reaction, Kinugasa reaction, Nazarov reaction, 1,2-Stevens rearrangement, Cannizzaro reaction, and cydopropanation. In comparison with the parent BOX ligands, the metal catalysts based on these TOX and SaBOX ligands usually exhibit higher efficiency and diastereo- and enantioselectivity with better impurity tolerance and stability. Moreover, in several TOX metal complex catalyzed reactions such as Friedel Crafts reaction and [3 + 2] cycloaddition, stereoselectivity could be switched based on reaction conditions. These ligands were particularly prominent in the remote controls of enantioselection such as the conjugate additions to alkylidene malonates and ring-opening/cyclization cascades of c-ydopropanes, for which high stereoselectivity is usually difficult to achieve due to the poor chiral communication. The works by us and other groups have demonstrated that the side arm strategy can be employed as a general principle for ligand and catalyst design and should not be limited to the BOX scaffolds and the reactions described in this Account. Wide application of the new strategy in organometallic homogeneous catalysis can be anticipated.
学科主题	金属有机化学
收录类别	SCI
原文出处	http://dx.doi.org/10.1021/ar800104y
语种	英语
内容类型	期刊论文
源URL	[http://ir.sioc.ac.cn/handle/331003/39097]
专题	上海有机化学研究所_金属有机化学国家重点实验室
作者单位	1.中科院上海有机化学研究所 2.天津化学化工协同创新中心
推荐引用方式 GB/T 7714	Liao SH,Sun XL,Tang Y. Side Arm Strategy for Catalyst Design: Modifying Bisoxazolines for Remote Control of Enantioselection and Related[J]. Accounts Chem. Res.,2014,47(8):2260-2272.
APA	廖赛虎,孙秀丽,&唐勇.(2014).Side Arm Strategy for Catalyst Design: Modifying Bisoxazolines for Remote Control of Enantioselection and Related.Accounts Chem. Res.,47(8),2260-2272.
MLA	廖赛虎,et al."Side Arm Strategy for Catalyst Design: Modifying Bisoxazolines for Remote Control of Enantioselection and Related".Accounts Chem. Res. 47.8(2014):2260-2272.