Application of chiral anion metathesis strategy in asymmetric transfer hydrogenation of isoquinolines was written by Shi, Lei;Ji, Yue;Huang, Wenxue;Zhou, Yonggui. And the article was included in Huaxue Xuebao in 2014.Name: (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:
Asym. hydrogenation of N-hetero aromatics offers a very straightforward and efficient method to obtain the corresponding chiral N-hetero cyclic saturated or partially saturated compounds As one of the most challenging substrates, asym. hydrogenation of isoquinolines has met with limited success probably because of lower reactivity and the catalyst deactivation resulted from strong coordination. Considering the prevalence of the chiral 1,2,3,4-tetrahydroisoquinoline motif in natural alkaloids and drug mols., the development of new catalyst system for asym. hydrogenation of isoquinolines is highly desirable and significant. Herein, a novel chiral anion metathesis strategy successfully applied for asym. transfer hydrogenation of isoquinolines is reported. N-Protected 1-substituted 1,2-dihydroisoquinolines were obtained with high yield and up to 79% ee in the presence of Hantzsch ester and chloroformate using chiral phosphoric acid as catalyst. The phosphate salt and the activated N-acyl isoquinolinium chloride undergo anion metathesis to form chiral contact ion pair, which leads to a highly enantioselective transfer hydrogenation of isoquinolines. After systematically investigating the effects of activating reagent, solvent, base, hydride donor and catalyst on this transfer hydrogenation reaction, the best result was achieved under the optimized condition as follows: 5 mol% H8-BINOL-derived chiral phosphoric acid as catalyst, 1.2 equiv 2,2,2-trichloroethyl chloroformate as activator, 1.5 equiv di-Me 2,6-diethyl-1,4-dihydropyridine-3,5-dicarboxylate as hydride donor, 1.5 equiv sodium carbonate as base and cyclohexane as solvent. The reaction is tolerant toward a broad range of aryl or alkyl 1-substituted isoquinoline substrates. This methodol. represents one of the rare examples of asym. hydrogenation of this challenging substrate. The utilizing of chiral anion metathesis strategy could enable chiral phosphoric acid to catalyze more asym. transformation process and further researching is ongoing in our laboratory 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: 1043567-32-3Name: (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. During the past two decades, tertiary phosphine catalysts have been applied extensively in a wide range of carbon–carbon and carbon–heteroatom bond-forming transformations. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.Name: (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