Tandem Cycloadditions with Nitronates 151
N
O
Me 2 Si
H
n-Pr
OSiMe 3
Si
Me
Me
O
N
OSiMe 3
H
n-Pr
N
O
Me 2 Si
H
n-Pr
OSiMe 3
Si
n-Pr
H
Me 3 SiO
Me
Me
I
II
11 (major)
12 (minor)
N N N
O
G
G
G
G
Scheme 22.12
In Summary
Nitronates are valuable 1,3-dipoles that can be easily obtained by reaction of a nitroalkene and an olefin in the presence of a Lewis acid. Frequently, nitronates are
involved in tandem [4+2]/[3+2] cycloaddion processes in which they are not necessarily isolated, but reacted with a dipolarophile either intra- or intramolecularly
to yield polycyclic compounds.
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 Denmark SE, Moon Y-C, Senanayake CBW
(1990) J. Am. Chem. Soc. 112:311-315 and by Young DGJ, Gómez-Bengoa E,
Hoveyda AH (1999) J. Org. Chem. 64:692-693.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
[4+2] and [3+2] Cycloadditions. Tandem reactions. FMO theory.
N
O
Me 2 Si
H
n-Pr
OSiMe 3
Si
Me
Me
O
N
OSiMe 3
H
n-Pr
N
O
Me 2 Si
H
n-Pr
OSiMe 3
Si
n-Pr
H
Me 3 SiO
Me
Me
I
II
11 (major)
12 (minor)
N N N
O
G
G
G
G
Scheme 22.12
In Summary
Nitronates are valuable 1,3-dipoles that can be easily obtained by reaction of a nitroalkene and an olefin in the presence of a Lewis acid. Frequently, nitronates are
involved in tandem [4+2]/[3+2] cycloaddion processes in which they are not necessarily isolated, but reacted with a dipolarophile either intra- or intramolecularly
to yield polycyclic compounds.
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 Denmark SE, Moon Y-C, Senanayake CBW
(1990) J. Am. Chem. Soc. 112:311-315 and by Young DGJ, Gómez-Bengoa E,
Hoveyda AH (1999) J. Org. Chem. 64:692-693.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
[4+2] and [3+2] Cycloadditions. Tandem reactions. FMO theory.