Figure 1. Wide range of applications of Feng’s chiral nitroxides
Chiral compounds are a very important class of compounds in the fields of medicine and materials. Among methods to obtain chiral compounds, asymmetric catalytic synthesis is one of the greenest and most efficient methods. Researchers' continued pursuit of chiral compounds has stimulated intensive research into the development of new catalysts for asymmetric reactions.
In principle, an ideal catalyst should be easy to structurally modify, cheap, stable, convenient to operate, and have high activity and selectivity. However, there is currently no universal chiral catalyst that can meet the above requirements.
Academician Feng Xiaoming of Sichuan University is a well-known chemist at home and abroad in the field of chiral organic synthesis. After 20 years of intensive research on new chiral catalysts and new reactions with high efficiency and selectivity, his team finally designed an ideal class of ligands and catalysts for asymmetric synthesis: N,N'-dioxy compounds (dinitroxide compound). This type of dinitroxide breaks through the traditional requirements for a rigid skeleton of ligands and is as rigid and soft as a "nunchuck". By controlling the way chemical substances meet in the reaction, they ensure that they combine in the expected way; Nitrogen compounds can also be adjusted to guide different reactions, making it possible to manufacture drugs according to the most effective single configuration rather than in the form of a mixture, and have very broad application prospects in drug synthesis. In 2018, Feng Xiaoming was awarded the Future Science Award for Material Science in recognition of his creative contributions in inventing new catalysts and new reactions, which provided new ways to synthesize organic molecules, especially drug molecules [1-3].
In addition, the Roskamp reaction is a reaction in which α-acetate diazoester and aldehydes are catalyzed by Lewis acids (Sc(OTf)3, BF3, GeCl2, etc.) to form β-keto acid esters. Since it involves a rearrangement process, there are many by-products in this reaction, but the main products are hydrogen migration products. After being improved by Feng Xiaoming's team, this reaction can achieve asymmetric conversion with a high yield and basically no by-products. This reaction is named Roskamp-Feng reaction (Figure 2).
Figure 2:Roskamp-Fengreaction, (using Feng's chiral nitroxide L3 (Cat. NO. 1595287) -Sc(OTf)3 Catalyst, the corresponding selectivity is as high as 98%, and the yield can reach 99%)
The advantages of chiral dinitroxide series products are as follows:
It has a strong broad spectrum [1] and is suitable for nearly twenty types of reactions, such as: asymmetric haloamination reactions of ketenes, α-amination reactions of ketones, etc. (as shown in Figure 1, Table 1), regardless of It’s your choice how you react;
The structure is both rigid and flexible, highly adjustable, and can be modified with substituents according to your reaction needs;
It can be used as an organic small molecule catalyst, or as a ligand to form a complex catalyst with a variety of metals (such as scandium, copper, nickel, magnesium, lanthanide metals, etc.);
Displays excellent stereoselectivity in a variety of reaction types;
Exclusively supplied by Bailingwei, high purity, various packaging specifications, sufficient stock.
Table 1. Some examples of applications of dinitroxide-metal complex catalytic asymmetric synthesis
| nitroxide metal complex | Application examples | Cat.No. (Dinitroxide/metal salt) |
|---|---|---|
| L1/Y(OTf)3 | Homologation of α-ketoesters and α-diazoesters[4] | 1595283 214543 |
| L2/Sc(OTf)3 | 1、Roskamp–Feng reaction[5]; 2、Electrophilic addition of α-diazoesters to ketones[6]; 3、ring expansion of isatins with α-diazoesters[7]; 4、Baeyer–Villiger oxidation[8]; 5、inverse electron-demand aza-Diels–Alder reaction[9]; 6、reduction reaction[10]; |
1595287 21-2000 |
| L2/Ni(BF4)2 | [8 + 2] cycloaddition[11]; | 1595287 93-2841 |
| L3/Mg(ClO4)2 | 1,3-dipolar cycloaddition of nitrile imines[12]; | 1595288 93-1246 |
| L2/L4/In(OTf)3 | Hetero-Diels–Alder reaction[13]; | 1595285 943368 |
| L4/Sc(OTf)3 | 1、α-Functionalization of 3-substituted oxindoles[14]; 2、epoxidation of enones with H2O2[15]; |
1595285 21-2000 |
| L4/Ni(ClO4)2 | Ene reaction[16]; | 1595285 93-2834 |
50 mg 250 m
NO-Feng-PCyPPi
向阳 翟
