Chemistry Reference
In-Depth Information
In 2010, Ma
et al.
reported that the Rh-catalyzed PKR of 1,3,4-alkatrien-2-
yldihydrofurans was achievable (Scheme 7.20).
44
The polyusubstituted dihydrofuryl cy-
clopententones were obtained in high yields. The product structures are commonly found
in natural products and bioactive molecules.
R
2
R
2
O
R
3
O
R
4
2-3 mol% [RhCl(CO)
2
]
2
CO (1 atm), DCE, 3 h, r.t.
O
CO
2
R
1
CO
2
R
1
R
5
R
5
R
3
R
5
R
5
R
4
71-96% yield
Scheme 7.20
Rh-catalyzed PKR of allene-alkene.
1] carbonylative cycloaddition of
tethered ene-cyclopropene (Scheme 7.21).
45
The cycloadducts were obtained in up to 89%
yield.
In 2010, Wang
et al.
illustrated a Rh-catalyzed [3
+
2
+
O
Z
5mol%[Rh(CO)
2
Cl]
2
DCE, 80
°
C, CO (Balloon)
1-12 h
Z
R
H
R
R
R
36-89% yield
Z=O,NTs,CH
2
R=Ph,
n
-Bu
Scheme 7.21
Rh-catalyzed PKR of tethered ene-cyclopropene.
1] homologous Pauson-Khand
reaction of 1-yne/ene-vinylcyclopropanes in 2010 (Scheme 7.22).
46
The desired bicyclic
cycloadducts were afforded in up to 92% isolated yield. The product derived from this
method was further utilized for the synthesis of furanoid sesquiterpene natural product,
Yu and co-workers disclosed a Rh-catalyzed [(3
+
2)
+
-agarofuran.
R
Me
Me
R
Me
O
O
5mol%[Rh(CO)
2
Cl]
2
Toluene, 80 °C, CO (0.2 atm)
1-168 h
Z
Z
n
n
Me
n
=1,2
50-92% yield
α
-agarofuran
Z = NTs, O, C(CO
2
Me)
2
R=H,Me,Ph
Scheme 7.22
Rh-catalyzed PKR of 1-yne/ene-vinylcyclopropanes.
Saito and co-workers first demonstrated the Rh-catalyzed intramolecular PKR of alkynyl-
carbodiimide for the synthesis of pyrroloindolones and pyrrolopyrrolinones in up to 85%
