手性双氮氧配体及其金属配合物不对称催化

Chiral N,N’-dioxide and their metal complexes in asymmetric catalysis

不对称催化是获得手性物质最高效的方法之一.针对效率和选择性的核心问题,发展高效高选择性的手性配体和催化剂是关键.不对称催化经过几十年的发展,其中手性金属配合物催化最受关注,应用也最广泛,但优势手性配体极其有限.因此,创制高效高选择性的优势手性配体是不对称催化领域最重要和最具挑战性的目标.在过去20年里,冯小明团队一直潜心催化不对称合成方面的研究,设计、合成了一类全新的具有柔性构象的手性双氮氧-酰胺化合物,被公认为一类优势手性配体和催化剂,打破了传统优势配体刚性构象的要求.建立了手性双氮氧-金属配合物催化剂库,高效高选择性实现了50多类重要的不对称反应,尤其是一些不对称催化新反应,为多个手性药物分子和天然产物的合成提供了简单、高效、精准、绿色途径.本文介绍了该类配体和催化剂的设计、合成以及手性双氮氧金属配合物催化的代表性不对称反应.这些原创性和系统性的研究工作,为手性科学的快速发展作出了重要贡献.

Chirality is a fundamental property of nature.Chiral compounds are closely related to life science,human health,material science,and so on.Asymmetric catalysis is one of the most efficient and important synthetic methodologies to obtain chiral compounds,which meets the requirement of green chemistry.Metal-catalyzed asymmetric reactions attract much attention in the past few years,and thousands of chiral ligands have been synthesized,however,widely applicable,so-called privileged chiral ligands are still very limited.Therefore,the design and synthesis of highly efficient and selective chiral ligands becomes the most important and challenging goal.Our group is committed to asymmetric catalysis and develope a novel type of C2-symmetric chiral ligand of N,N’-dioxide amide compounds which is easily synthesized from cheap chiral amino acids and amines.Such conformationally flexible privileged ligands break through the notion of the rigid feature of previously privileged ligands.Naturally,it would guide the creation of new ideal chiral ligands and catalysts.N,N’-dioxides are not only used as bifunctional organocatalysts,but also provide an arsenal of chiral metal complexes upon coordination with a variety of metal salts,such as alkaline-earth metal salts,transition metal salts and rare-earth metal salts.This powerful catalyst system has been proved to be highly effective for more than fifty types of asymmetric reactions with wide substrate generality under mild conditions,including carbon-carbon bond formation,and carbon-heteroatom bond formation reactions.The concerns of controlling chemo-,regio-,and stereoselectivity of involved reactions are well addressed.Some new and challengling asymmetric reactions are realized,for intances,the first asymmetric Roskamp reaction is achieved with a N,N’-dioxide/Sc(Ⅲ)complex at low catalyst loading,which updates the comment aboutβ-keto esters in text of Organic Chemistry,Oxford,and the reaction is amended as"Roskamp-Feng reaction"in Elsevier’s Organic Synthesis Based on Name Reactions.The asymmetric amination of ketones withα-diazoesters shed light on the diversity of diazo chemistry.N,N’-dioxide/La(Ⅲ)complex catalyzed sulfa-Michael reaction exhibits very strong chiral amplification effect.N,N’-dioxide/Ni(Ⅱ)complex acts as both chiral Lewis catalyst and metal-carbene promotor in Doyle-Kirmse reaction,[2,3]-Stevens rearrangement and SommeletHauser rearrangement of a new type of designedα-diazo pyrazoleamides.Such the creation of catalytic systems and catalytic asymmetric methods provide simple,efficient,precise,green access to several biologically active drug molecules and natural products,such as Paroxetine,Pregabalin,Thiazesim,KAE609 and so on.Now,N,N’-dioxides have become commercially available chiral ligands and have been successfully applied by many research groups and companies.The above original and systematic research achievements make important contribution to the chirality science.