Topics in Current Chemistry (2019) 377:23
1 3
such cyclic imine benzoxazine substrates 32, the reaction occurred with an involvement of noncovalent interactions (including electrostatic and dispersion interactions,
as shown in 36), that is, the hydroxycyclopentadienyl ligand and the iron complex
do not change oxidation state during the catalytic cycle, rather than the redox mechanism. The H 2 splitting assisted by phosphate promotion is the rate-limiting step.
Scheme 10 Enantioselective hydrogenation of quinoxalines and 2H-1,4-benzoxazines
Scheme 11 Hopmann’s mechanism of iron complex-catalyzed asymmetric hydrogenation
Reprinted from the journal
162
1 3
such cyclic imine benzoxazine substrates 32, the reaction occurred with an involvement of noncovalent interactions (including electrostatic and dispersion interactions,
as shown in 36), that is, the hydroxycyclopentadienyl ligand and the iron complex
do not change oxidation state during the catalytic cycle, rather than the redox mechanism. The H 2 splitting assisted by phosphate promotion is the rate-limiting step.
Scheme 10 Enantioselective hydrogenation of quinoxalines and 2H-1,4-benzoxazines
Scheme 11 Hopmann’s mechanism of iron complex-catalyzed asymmetric hydrogenation
Reprinted from the journal
162