cope rearrangement -...
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StereochemistryH
H
OH
H
HO H
H
H
H
RR
O O
R R
HH H
H H H H
Me Me OH
Me
HO H
Me
HMeMeMe Me
O O HH H
H H H H
H
Me Me OH H
O HHMeMe
Me Me
O O HH Me
H
Me
H Me H
MeH
Me Me
(Anionic) Oxy-Cope Rearrangement
Schreiber, S. L.; Santini, C. Tetrahedron Lett. 1981, 22, 4651.
O
O
O
18-crown-6OO
O
18-crown-6
Aza-Cope Rearrangement
aza-Cope–Mannich
Knight, S. D.; Overman, L. E.; Pairaudeau, G. J. Am. Chem. Soc. 1995, 117, 5776.
Ireland–Claisen RearrangementLiO TMSO TMSO
LDATHF
–78 ºCO
LiO
Me3SiCl O
TMSO
O
TMSO
O
O
LDA O
LiO
Me3SiCl O
TMSO
O
TMSO
LDATHF/HMPA
–78 ºC
O Me3SiCl O O
Ireland, R. E.; Mueller, R. H.; Willard, A. K. J. Am. Chem. Soc. 1976, 98, 2868.
HMPA: hexamethylphosphoramide
HMPT: hexamethylphosphorous triamide
Carroll–Claisen Rearrangement
E h Cl i R tEschenmoser–Claisen RearrangementNMe2
OMNMe2
NMOH OMe
OMeOMe
OHO
NMe2MeO
O
NMe2
H
NMe2
O
NMe2
OO
m [m,n]
1 n
[m,n]
suprafacial-suprafacial1'
total number of electrons = (4n + 2) ....... allowedtotal number of electrons (4n 2) ....... allowed
[1,n]-Shift (Suprafacial Shift)....(4n + 2) electrons
Fleming, I. Molecular Orbitals and Organic Chemical Reactions, John Wiley & Sons: West Sussex, 2009.
R R R
[1,7]-Shift R R R
100 ºC OHHD +
OHD H
OH
Hoeger, C. A.; Okamura, W. H. J. Am. Chem. Soc. 1985, 107, 268.Fleming, I. Molecular Orbitals and Organic Chemical Reactions, John Wiley & Sons: West Sussex, 2009.