- Facile Isomerization of Trimethylsilyl Ketene Acetals to α-Trimethylsilyl Esters Catalyzed by Lanthanoid Trifluoromethanesulfonates
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Migration of trimethylsilyl group from oxygen to α-carbon in silyl ketene acetals is effectively catalyzed by lanthanoid triflates under mild conditions.Scope and limitation of this rearrangement are presented.
- Makioka, Yoshikazu,Taniguchi, Yuki,Takaki, Ken,Fujiwara, Yuzo
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p. 645 - 648
(2007/10/02)
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- The Highly Regioselective Carbonylation of Vinylsilanes
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The hydroesterification of vinylsilanes, catalyzed by transition-metal complexes, afforded both β-silyl esters 2 and α-silyl esters 3 in high yield.The Pd(II) complex-catalyzed reaction showed high β-regioselectivity, whereas the Co2(CO)8-catalyzed reaction showed high α-regioselectivity.Vinylsilanes which bore trialkyl-, diphenylmethyl-, dimethylethoxy-, trimethoxy-, diphenylfluoro-, and difluorophenylsilyl groups were regioselectively, and in some cases regiospecifically, hydroesterified.Pd(II) complexes were also shown to be effective catalysts of the hydrocarboxylation of vinylsilanes.Hydrocarboxylation was β-regiospecific and gave excellent yields of β-silyl carboxylic acids.Reasonable mechanisms for the reactions are described.
- Takeuchi, Ryo,Ishii, Naomi,Sugiura, Masaharu,Sato, Nobuhiro
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p. 4189 - 4194
(2007/10/02)
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- Palladium Catalyzed Coupling Reaction of α-Bromo Ketones with Hexabutylditin
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Palladium-catalyzed reaction of α-bromo ketones with hexabutylditin in the presence of trimethylsilyl chloride gave enol trimethylsilyl ether in moderate to good yields.
- Kosugi, Masanori,Koshiba, Mamoru,Sano, Hiroshi,Migita, Toshihiko
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p. 1075 - 1076
(2007/10/02)
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- Reactions of Trialkylsilyl Trifluoromethanesulfonates, II. - Synthesis of O-Alkyl-O-(trialkylsilyl)ketene Acetals and 2-(Trialkylsilyl)carboxylates
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Alkyl carboxylates 2 are silylated by trialkylsilyl triflates 1 in the presence of triethylamine (3) to yield ketene acetals 4.In reactions of the esters 6 mixtures of ketene acetals 7 and at the α-carbon silylated esters 8 are obtained.Ethanoic acid esters and lactones are doubly silylated to give the products 11, 12, and 15, respectively.Under suitable conditions silylation of the esters 10 gives rise to the 2-trimethylsilylethanoic acid esters 13.The thermodynamically more stable products are obtained.Product distributions depend on the structure of the esters and the silylating agents 1.
- Emde, Herbert,Simchen, Gerhard
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p. 816 - 834
(2007/10/02)
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- HYDROFORMYLATION AND CARBOXYLATION OF OLEFINS IN PRESENCE OF STANNYLENE COMPLEXES OF METAL CARBONYLS
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Stannous chloride is an activator for chromium molybdenum, and tungsten hexacarbonyls as catalysts in hydroformylation and carboxylation processes.It is considered that the catalysts of the processes are stannylene complexes formed in situ from chromium, molybdenun, and tungsten hexacarbonyls and stannous chloride.
- Magomedov, G. K.-I.,Morozova, L. V.
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p. 1947 - 1950
(2007/10/02)
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