Morita-baylis-hillman reactions between conjugated nitroalkenes or nitrodienes and carbonyl compounds
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Title |
Morita-baylis-hillman reactions between conjugated nitroalkenes or nitrodienes and carbonyl compounds
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Creator |
DEB, I
SHANBHAG, P MOBIN, SM NAMBOOTHIRI, INN |
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Subject |
alkenes
alpha-hydroxyalkylation c-c coupling nitroalkenes morita-baylis-hillman (mbh) reaction synthetic methods alpha-keto esters functionalized 3-substituted 3-hydroxy-beta-lactams remarkable rate acceleration methyl vinyl ketone dicarbonyl compounds anticancer activity activated alkenes michael addition nitroaliphatic compounds synthetic applications |
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Description |
Morita-Baylis-Hillman (MBH) reactions between conjugated nitroalkenes or nitrodienes and various carbonyl compounds such as glyoxylate, trifluoropyruvate, pyruvaldehyde, oxomalonate, ninhydrin, and formaldehyde have been extensively investigated. The reactions proceeded smoothly in the presence of DMAP (40-100 mol-%) in acetonitrile and in some cases also in that of imidazole (100 mol-%) in CHCl(3) or THF, to provide the multifunctional adducts in good to excellent yields. The reactions catalyzed by DMAP in acetonitrile were superior to the imidazole-catalyzed reactions both in terms of the rate of reaction and in terms of the isolated yields of the MBH adducts. The catalytic roles played by DMAP and imidazole in these reactions, vis-a-vis other MBH catalysts such as DABCO, are attributed primarily to resonance stabilization of the initial zwitterionic intermediates. Whereas the E isomers are the major or exclusive products in the cases of glyoxylate, pyruvaldehyde, and formaldehyde, the Z isomers predominate in the cases of trifluoropyruvate and ninhydrin. Interestingly, oxomalonate forms E isomers with aromatic nitroalkenes and Z isomers with aliphatic ones. These selectivities and the formation of unusual deconjugated products in the case of certain beta-alkyl-nitroethylenes have been explained. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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Publisher |
WILEY-V C H VERLAG GMBH
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Date |
2011-10-12T11:19:38Z
2011-12-15T09:16:05Z 2011-10-12T11:19:38Z 2011-12-15T09:16:05Z 2009 |
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Type |
Review
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Identifier |
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY,(24)4091-4101
1434-193X http://dx.doi.org/10.1002/ejoc.200900475 http://dspace.library.iitb.ac.in/xmlui/handle/10054/13755 http://hdl.handle.net/100/2988 |
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Language |
en
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