Schwenk, R.; Togni, A. published an article in 2015, the title of the article was P-Trifluoromethyl ligands derived from Josiphos in the Ir-catalysed hydrogenation of 3,4-dihydroisoquinoline hydrochlorides.Reference of (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl carbonochloridate And the article contains the following content:
The synthesis of mono P-trifluoromethyl and therefore P-stereogenic Xyliphos-derived ligands CpFeC5H3(PPhCF3)(CMeHP(xyl)2) (5, xyl = C6H3Me2-3,5) and their application in the Ir-catalyzed enantioselective hydrogenation of 1-substituted 3,4-dihydroisoquinolinium species (DHIQ) are reported. The ligands were prepared following previous procedures involving the reaction of a bis(trifluoromethyl)phosphine with lithiated (R)-Ugi amine (R)-CpFeC5H3Li(CHMeNMe2) (1). Chloroiridium(I) cyclooctadiene precatalysts containing these new partially electron-poor ligands are poorly active in the hydrogenation of free 1-phenyl-3,4-dihydroisoquinoline (12a). However, the corresponding hydrochloride 12a·HCl was smoothly reduced at 55-60° and 100 bar H pressure. The (SP)-configured ligand (SP)-5 yielded significantly higher enantioselectivity in hydrogenation experiments than its P-stereoisomeric counterpart (RP)-5. These new ligands were subsequently applied in the hydrogenation of twelve different 1-substituted 3,4-DHIQ chlorides. Good to excellent enantioselectivity was observed for substrates bearing relatively large substituents in position 1, reaching 96% ee for 1-Ph-DHIQ chloride 12a·HCl without the help of any additives. Furthermore, an interesting counterion effect was found with chloride being the best and hexafluorophosphate being very detrimental to enantioselectivity. The experimental process involved the reaction of (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl carbonochloridate(cas: 14602-86-9).Reference of (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl carbonochloridate
The Article related to xyliphos fluoromethyl iridium catalyst preparation hydrogenation enantioselective dihydroisoquinoline hydrochloride, fluoromethyl phosphinylferrocenyl iridium preparation hydrogenation catalyst enantioselective hydroisoquinoline hydrochloride, crystal mol structure fluoromethyl xyliphos platinum iridium preparation and other aspects.Reference of (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl carbonochloridate
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