Ru
Ph
PCy 3
Cl
Cl
Ph-Me, 110 °C
(20 mol %)
N
N
Mes
Mes
124
N
CO 2 t-Bu
Boc
HO
H
OTBS
H
N
CO 2 t-Bu
Boc
O
H
OH
H
OAc
[Ir(cod)Cl] 2
(10 mol %)
Na 2 CO 3
PhMe, 100 °C
123
1)
2) TBAF, THF, rt
N
O
H
H
CO 2 t-Bu
Boc
OH
N
O
H
HO
N
O
O
O
OH
H
S S
Aranotin
122
95%
99%
Scheme 48 RCM between an enol ether and an allylic alcohol to reach the oxepin ring of aranotin
Ru
Cl
Cl
N
N
Mes
Mes
OH
OCO 2 Me
Ph
O
SO 2 NMe 2
O
Ph
1) [Ir(cod)Cl] 2 (2 mol %)
phosphoramidate P
(4 mol %)
Cs 2 CO 3 (1.1 equiv)
THF, 50 °C, 24 h
2) cat. I (2 mol %)
127 (ee = 94%)
O
O
P N
2-Napht
2-Napht
P
Zhan's catalyst, I
125
126
81%
Scheme 49 Combination of iridium and ruthenium catalysis to access enantioenriched
benzoxepine 127
Ru
Ph
PCy 3
PCy 3
Cl
Cl
OBn O
OBn
OBn
O
OBn
OBn
OBn
O
OBn
OBn
OBn
129
CH 2 Cl 2
(GI 5 mol %)
GI (5 mol %)
Ph-Me, rt
then NaOH
and i-PrOH, 110 °C
130
82%
68%
128
Scheme 50 Complementary approach to oxepene 129 or 130 from the same diene 128
Synthesis of Seven-Membered Ring Ethers and Lactones
305