proved to be highly efficient in the asymmetric hydrogenation of substituted dibenzo
[b,f][1,4]oxazepines, benzodiazepinones, and benzodiazepines (ees up to 96%,
Fig. 42a) [272, 273]. More recently, Zhou et al. reported the asymmetric hydrogenation of 6-substituted 5H-benzo[d]benzofuro[3,2-b]azepines using a BIPHEP-type
ligand L46 (ees up to 91%, Fig. 42b) [274]. 2,4-Diaryl-1,5-benzodiazepines and
2,4-diaryl-3H-benzo[b]azepines has been also successfully hydrogenated (ees up to
99% and drs up to >20:1) using aminophosphine-pyridine ligand L47 (Fig. 42c)
[275] and a dendritic PHOX derivative [276, 277]. Benzoxazinone derivatives have
Fig. 40 (R)-Difluorphos, (R)-P-Phos, and (R
ax ,S,S)-Siphos-pe ligands successfully used in the AH
of quinoline derivatives
Fig. 41 Representative examples of 6-membered cyclic imines other than quinoline derivatives
and iminium salts successfully hydrogenated using SegPhos, Difluorphos, and phosphine-phosphite
ligand L45
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