Level 2 – Case 24
162
O
OMe
OMe
Ph
H H
3
O
OMe
OMe
C
Ph
H
H
OMe
O
H
Ph
O
OMe
OMe
H
H
+
2
8e
conrotatory
6e
disrotatory
4
8
9
Ph
H
Scheme 24.5
In Summary
Thermal rearrangements of cyclobutenone 1 yield naphthofuran 3 or bicyclo[4.2.0]octadienyl-fused cyclobutenone 4 depending on the reaction conditions.
The rearrangements involve a series of cascade electrocyclic ring opening and ring
closures that require the initial formation of alkynyl cyclobutenone 2 in the reaction medium.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Hergueta AR, Moore HW (2002) J. Org.
Chem. 67:1388-1391.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Electrocyclic ring closure and ring opening processes.
162
O
OMe
OMe
Ph
H H
3
O
OMe
OMe
C
Ph
H
H
OMe
O
H
Ph
O
OMe
OMe
H
H
+
2
8e
conrotatory
6e
disrotatory
4
8
9
Ph
H
Scheme 24.5
In Summary
Thermal rearrangements of cyclobutenone 1 yield naphthofuran 3 or bicyclo[4.2.0]octadienyl-fused cyclobutenone 4 depending on the reaction conditions.
The rearrangements involve a series of cascade electrocyclic ring opening and ring
closures that require the initial formation of alkynyl cyclobutenone 2 in the reaction medium.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Hergueta AR, Moore HW (2002) J. Org.
Chem. 67:1388-1391.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Electrocyclic ring closure and ring opening processes.