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Synthesis of alkenes by isomerizations
Recent Literature
O3ReOSiPh3 promotes the 1,3-isomerization of various
allylic alcohols. Two different strategies allow the selective formation of
a single isomer. The first strategy utilizes the formation of a conjugated
alkene to ensure a high selectivity. The second strategy employs N,O-bis(trimethylsilyl)acetamide
(BSA) as an additive to remove the product from the reaction equilibrium and
works well for the isomerization of tertiary allylic alcohols.
C. Morrill, R. H. Grubbs, J. Am. Chem. Soc.,
2005, 127, 2842-2843.
C. Morrill, R. H. Grubbs, J. Am. Chem. Soc.,
2005, 127, 2842-2843.
Substituted benzofurans were synthesized from their corresponding substituted
1-allyl-2-allyloxybenzenes using ruthenium-catalyzed C- and O-allyl
isomerization followed by ring-closing metathesis.
W. A. L. van Otterlo, G. L. Morgans, L. G. Madeley, S. Kuzvidza, S. S. Moleele,
N. Thornton, C. B. de Koning, Tetrahedron, 2005,
61, 7746-7755.
Pd(PPh3)4-catalyzed isomerization of
methylenecyclopropanes (MCPs) proceeds smoothly
at 80°C in acetic acid and toluene to give 1-substituted or 1,1-disubstituted
dienes in good to excellent yields. The mechanism is discussed.
M. Shi, B.-Y. Wang, J.-W. Huang, J. Org. Chem., 2005, 70, 5606-5610.
Aryl-substituted cyclopropyl carbinol derivatives undergo a facile
stereoselective rearrangement catalyzed by In(OTf)3 in
dichloromethane under sonication to produce the substituted conjugated all-trans-butadienes.
B. C. Ranu, S. Banerjee, Eur. J. Org. Chem., 2006, 3012-3015.
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