O
N
H
Q
MeO
+ HN
O
Cu(OAc)2 (10 mol%)
Ag2CO3 (13 mol%)
NMO (2.0 eq)
NMP, 110 ºC
O
N
H
Q
MeO
N
O
87%
(31)
N
N
NH
O
Oxa
+
N
N
H 2 N
Cu(OAc)2 (2.0 eq)
DMSO, 80 ºC, air
N
N
NH
O
Oxa
H
N
N
N
66%
(32)
By using a picoline-type director, anilides can also couple with alkylamines in a
dehydrogenative manner to form the corresponding 1,2-diaminobenzene derivatives (Eqs. 33 and 34) [59, 60]. The hypervalent I(III) reagent, PhI(OAc) 2 is a
critical oxidant, and the reaction occurs under relatively mild conditions (rt–80
C).
The unique ortho-regioselectivity observed in the reaction of 1-naphthylamine and
preliminary deuterium-labeling experiments suggests a single electron transfer
(SET) mechanism, although the detailed pathway still remains obscure.
(33)
(34)
4 C–H/X–H Coupling with Other Heteroatom
Nucleophiles
Some heteroatom nucleophiles other than amines also couples with aromatic C–H
bonds under appropriate copper-based conditions to make the corresponding C–X
bonds efficiently.
Copper-Mediated Intermolecular C–H/C–H and C–H/N–H Couplings via. . .
57