189
+ H 2
[Cp 2 Fe] (10 mol%)
MeOH/THF (1:2),nBu 4 NBF 4
0 or -30
o
C
RVC
P t
LiCp (30 mol%)
N
CO 2 Me
F
O
R 2
H
H
R 1
N
O
CO 2 Me
F
R 2
R 1
N
O
CO 2 Me
F
N
79%
N
O
CO 2 Me
F
75%
MeO 2 C
NHBoc
N
O
CO 2 Me
F
72%
O
N
O
CO 2 Me
F
OH
76%
N
O
CO 2 Me
F
80%
N
O
CO 2 Me
F
75%
O
NHPh
O
122
123
Scheme 5.48 Electrochemical dehydrogenative coupling synthesis of C3-fluorinated oxindoles
Pt (+) Pt (-) : I = 7 mA
KI (0.15 M),
DMF/H 2 O, rt, 3 h
undivided cell
N
H
R 2
R 3
R 1
H H
N
H
R 2
R 3
R 1
N
H
CO 2 Et
96%
N
H
CO 2 Me
61%
N
H
Ph
CO 2 Et
80%
N
H
Ph
COPh
62%
+ H 2
124
125
Scheme 5.49 Electrocatalytic intramolecular oxidative annulation of N-aryl enamines
5 Fourth-Generation Oxidative Cross-Coupling Reactions