16
[43]. Remarkably, a variety of functional groups were tolerated. Later on, by
employing ionic liquid solvent system and 1,2-dichloroethane as the oxidant, an
iron-catalyzed oxidative homo-coupling of aryl- and alkynylmagnesium reagents
was achieved (Scheme 2.13) [44].
In the presence of 1,2-dihalogenoethanes as the oxidant, silver- and manganesecatalyzed oxidative homo-coupling of alkyl- and arylmagnesium reagents occurred
to afford the corresponding symmetrical biaryls and alkanes (Scheme 2.14) [45, 46].
ArMgBr
Ar Ar
FeCl 3 (1 mol%)
ClCH 2 CH 2 Cl, [P 444ME ][NTf 2 ]/THF
0-25 o C, 5-30 min
OMe
P
Bu
Bu
Bu
NTf 2
R
MgBr
FeCl 3 (1 mol%)
lCH 2 CH 2 l
[P 444ME ][NTf 2 ]/THF
0 o C, 10-30 min
R
R
[P 444ME ][NTf 2 ]
R = Aryl
Alkenyl
TMS
Scheme 2.13 Fe-catalyzed oxidative homo-coupling of aryl- and alkynylmagnesium reagents
RMgX
AgOTs (1 mol%)
BrCH 2 CH 2 Br, THF
r. t., 30 min
R R
R = Alkyl
X = Br, Cl
ArMgCl
MnCl 2 (10 mol%)
ClCH 2 CH 2 Cl, THF
r. t., 2-12 h
Ar Ar
Scheme 2.14 Ag- and
Mn-catalyzed oxidative
homo-coupling of alkyland arylmagnesium
reagents
FeCl 3 (3 mol%)
ClCH 2 CH 2 Cl, THF
r.t., 10 min
FeCl 3 (3 mol%)
BrCH 2 CH 2 Br, THF, r.t., 10 min
MgBr
OMe
MeO
OMe
73%
MgBr
NC
FeCl 3 (3 mol%)
ICH 2 CH 2 I, THF
-40 o C, 2 h
NC
CN
75%
MgBr
MeO
MeO
OMe
90%
Scheme 2.12 Fe-catalyzed oxidative homo-coupling of functionalized arylmagnesium reagents
H. Zhang