Chiral phosphoric acid-catalyzed asymmetric cascade reaction of C(3) substituted indoles and methyl vinyl ketone was written by Duan, Dehe;Yin, Qin;Wang, Shouguo;Gu, Qing;You, Shuli. And the article was included in Huaxue Xuebao in 2014.Application In Synthesis of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide This article mentions the following:
Fused indolines bearing a chiral quaternary carbon center at the C(3) position represented very important moieties widely existed in natural products and biol. active compounds Various approaches to access these important scaffolds had been developed. Among them, asym. dearomatizationcyclization cascade reaction was the most concise and effective method by using indole derivatives as starting material. However, the documented reports mainly employed tryptamine or tryptophol derivatives, providing indoline products, such as pyrroloindolines or furoindolines. Therefore, the development of other type of indole derivatives allowing structural diversity was highly desirable. In this paper, an efficient asym. Michael additioncyclization cascade reaction of indole derivatives with Me vinyl ketone (MVK) was developed. After screening various phosphoric acids in the reaction of indole derivative (1a) with MVK, this cascade reaction delivered the dearomative product (2a) in 77% yield and 95% enantiomeric excess in the presence of (R)-SPINOL-derived chiral phosphoric acid (R)-4c with 5Å mol. sieves as additive in CHCl3 at room temperature Under the optimized reaction conditions, a wide range of substituted indole derivatives bearing both electron-donating and electron-withdrawing groups had been tested. In all cases, the cascade dearomatization reaction proceeded smoothly to afford their corresponding indolo[2,3-b]quinoline products in moderate to good yields and excellent enantioselectivity. The absolute configuration of the products was then determined as (5aR,10bR) by an X-ray crystallog. anal. of a single crystal of enantiopure 2. Moreover, this catalytic system was also feasible in a gram-scale reaction without erosion of enantiomeric excess. And 1.25 g of product 2a could be prepared under the identical conditions in 91% yield and 93% ee. In the experiment, the researchers used many compounds, for example, (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide (cas: 1043567-32-3Application In Synthesis of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide).
(11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide (cas: 1043567-32-3) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Application In Synthesis of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis