18296-04-3Relevant articles and documents
Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group
Fleming, Ian,Patel, Shailesh K.,Urch, Christopher J.
, p. 115 - 124 (2007/10/02)
γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.
NOVEL SYNTHESIS OF β-SILOXY ESTERS BY CONDENSATION OF CARBONYLS AND TRIMETHYLSILANE WITH α,β-UNSATURATED ESTERS CATALYZED BY RhCl3
Revis, Anthony,Hilty, Terrence K.
, p. 4809 - 4812 (2007/10/02)
A novel one pot reaction of α,β-unsaturated esters with carbonyls and trimethylsilane gave good yields of β-siloxy esters.This RhCl3 catalyzed method improves upon the two step reaction of silyl ketene acetals with carbonyls.
The Catalyzed Reaction of α,β-Unsaturated Esters with Various Hydrosilanes
Takeshita, Kenji,Seki, Yoshio,Kawamoto, Kazuaki,Murai, Shinji,Sonoda, Noboru
, p. 4864 - 4868 (2007/10/02)
The Co2(CO)8-catalyzed reaction of acrylic acid esters (methyl acrylate, ethyl acrylate, and butyl acrylate) with HSiEt2Me gave the corresponding (E)-3-silylacrylate in high yields, along with only a small amount of β-adducts, when the esters were used in
SILYL- AND GERMYL-CYCLOPROPANONES
Zaitseva, G. S.,Krylova, G. S.,Perelygina, O. P.,Baukov, Yu. I.,Lutsenko, I. F.
, p. 1935 - 1947 (2007/10/02)
1.The reactions of silylcyclopropanones with compounds containing a mobile hydrogen atom and also with alkoxy, dialkylamino, and dialkoxyphosphinooxy derivatives of Group IVB elements give adducts at the carbonyl group of the cyclopropanone, and, when heated, these undergo isomerization with opening of the three-membered ring exclusively at the C1-C2 bond and with the formation of β-heteroelement-substituted propionic derivatives. 2.Acetic acid and bis(trifluoroacetic) anhydride in reaction with (trimethylsilyl)cyclopropanone form relatively stable products of addition at the carbonyl group. 3.Bromine and iodotrimethylsilane react with silylcyclopropanones with breakage of the C2-C3 bond of the cyclopropanone ring and give the corresponding O- and C-isomeric derivatives of α-silylated ketones containing halogen atoms in the molecule. 4.The reactions of silyl- and germyl-cyclopropanones with diazomethane and with azido-silanes and -germanes can provide a method of synthesis of heteroelement-substituted (Si, Ge) cyclobutanones and β-lactams.
NEW FUNCTIONAL ALLYLIC LITHIUM REAGENTS: GEM-DIALKOXYALLYLLITHIUM REAGENTS: A USEFUL ROUTE TO β-SILYL- AND β-STANNYLPROPIONATE ESTERS
Seyferth, Dietmar,Mammarella, Robert E.,Klein, Helmut A.
, p. 1 - 8 (2007/10/02)
The reaction of sec-butyllithium with acrolein dialkyl acetals in THF or in THF/Et2O/pentane at -95 deg C results in formation of gem-dialkoxyallyllithium reagents, Li.These react with organosilicon and organotin chlorides to give ketene acetals, R3SiCH2CH=C(OR)2 and R3SnCH2CH=C(OR)2.The acid hydrolysis of these products produces β-substituted propionic acid esters, R3SiCH2CH2CO2R and R3SnCH2CH2CO2R.Reactions of these lithium reagents with allyl bromide gave esters of 5-hexenoic acid, CH2=CH(CH2)3CO2R (R=Me, Et).
