“…Oxidation with selenium failed for 4b , but 4a could be successfully oxidized ( 31 P NMR 53.5 ppm). The 31 P– 77 Se coupling constant of 765 Hz in selenido- 4a lies within the range reported for phospholane–selenides and indicates moderate σ basicity on phosphorus (compare 732 Hz for SePPh 3 ).…”
“…Oxidation with selenium failed for 4b , but 4a could be successfully oxidized ( 31 P NMR 53.5 ppm). The 31 P– 77 Se coupling constant of 765 Hz in selenido- 4a lies within the range reported for phospholane–selenides and indicates moderate σ basicity on phosphorus (compare 732 Hz for SePPh 3 ).…”
“…14 The 31 P-77 Se coupling constants for the bisselenides of L1 and L2 (Table 5) lie within the range reported for phospholane selenides (710-780 Hz). 15 The phosphorus atoms of L1 and L2 in the ortho position showed J Se,P = 713 and 718 Hz, respectively, similar to the value registered for the corresponding MeDuPhos derivative (712 Hz). The coupling constants of the phospholane selenides in the α-position are significantly higher (727 Hz for L1 and 726 Hz for L2) and closer to the value reported for Se=PPh 3 (732 Hz).…”
Section: Scheme 3 Synthesis Of Ligand L1 and L2supporting
Bisphospholane Josiphos-type ligands were synthesized in high yields employing electrophilic and nucleophilic phospholane synthons. Full characterization data including solid-state structures of the diastereomeric ligands are reported. These ligands resulted in active and enantioselective iridium catalysts for the asymmetric hydrogenation of imines. Pronounced cooperative effects of the chiral elements within the ligand structure were observed and enantioselectivities of up to 74% ee were achieved.
“…More recently, Börner et al reported a second type of monodentate phosphole, based on tartaric acid, which allowed easy integration of chiral information [22]. The key step was a double hydrophosphination (Scheme 10).…”
Section: Design and Synthesis Of Chiral Monophosphinesmentioning
confidence: 99%
“…Immediately after, Börner et al reported a second type of monodentate phospholes, based on tartaric acid [22]. The obtained ligands were tested in the asymmetric hydrogenation of ␣-and -dehydroamino acid derivates.…”
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