From allylic alcohols to chiral tertiary homoallylic alcohol: palladium-catalyzed asymmetric allylation of isatins

Asymmetric Hydrogenation of Unfunctionalized Enamines Catalyzed by Iridium Complexes of Chiral Spiro N,N‐Diarylphosphoramidites

“…A series of spiro phosphoramidite ligands (R)-2 with different N-aryl or N,N-diaryl groups were synthesized by our previous method. 8 The ligands (R)-2 were compared in the hydrogenation of enamine 3a and the results were listed in Table 1. Introduction of an electron-withdrawing substituent such as a para-chloro (ligand 2b) into N-phenyl groups of the ligand has little effect on the enantioselectivity of the reaction (Table 1, Entry 2).…”

Application of Hydroxyporphyrins-based Phosphite-type Ligands to Asymmetric Pd-Catalyzed Allylic Substitution Reactions

“…Ligands 4a-c and 5 were obtained in yields varying from 76 to 85 %; they can be stored in the solid form under dry conditions at room temperature for at least a few months with minimal degradation. Compounds 4a-c and 5 were fully characterized by 31 P, 1 H, and 13 C NMR spectroscopy, MALDI TOF/ TOF mass spectrometry as well as by elemental analysis. Porphyrin-appended ligands 4a, 4c and 5 are metal-free, diamidophosphite-porphyrinato-zinc(II) compound 4b was prepared for comparison purposes.…”

“…Also, they can be easily prepared from readily available starting materials via simple condensation processes, including those involving parallel and solidphase synthetic procedures. [5,7,11,12,[18][19][20][21][22][23][24][25][26][27][28][29][30][31] In the case of P*-chiral phosphite-type ligands the presence of a stereogenic donor of phosphorus atom significantly promotes successful asymmetric induction in the key step of the catalytic cycle. [2,17,18,32,33] Catalytic systems based on chiral supramolecular ligands with phosphite moiety have recently attracted increasing attention.…”

Catalytic Enantioselective Addition of Me2Zn to Isatins

“…Therefore, in the last years, the asymmetric synthesis of chiral 3-substituted-3-hydroxy-2-oxindoles have become a hot topic in organic synthesis [12,13]. The synthesis includes allylation [14,15], crotylation [16], arylation [17,18] and decarboxylative cyanomethylation [19] of isatines, as well as the palladium catalyzed intramolecular arylation [20]. The particular interest is the 3-hydroxy-3-methyl-2-oxindole structure, which is present in several natural products such as convolutamydine C [21] and synthetic compounds with biological activities or drug candidates such as compound 2a [22], compound A [23] and compound B [24] (Figure 1).…”