M O
H
O
R 2
R 1
O
OH
OH
R 2
R 1
M H
M
O
H
R 1
R 2
M O
R 1
R 2
H
M
O
H
H
M
H
H
M
H
H
O
R 1
R 2
M O
R 1
R 2
H
H
M
OH
O
O
R 2
R 1
OH
R 2
R 1
Scheme 70 Metal monohydride (top) and metal dihydride routes (bottom) for the TH of carbonyl
compounds using 2-propanol as the hydrogen donor
M N
M N
H
H
OH
O
O
R 2
R 1
OH
R 2
R 1
M N
H
H
O
R 1
R 2
Scheme 71 Metal-ligand bifunctional mechanism for the TH of carbonyl compounds using
2-propanol as the hydrogen donor (left) and the transition state for the concerted transfer of the
two hydrogen atoms from the metal-ligand platform to the substrate (right)
Recent Advances in Iridium-Catalysed Transfer Hydrogenation Reactions
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