10545-34-3Relevant articles and documents
CARBANIONEN-UMLAGERUNGEN DURCH INTRAMOLEKULARE 1,ω-PROTONVERSCHIEBUNG. II. ZUR REAKTIONSWEISE VON 3-, 4- UND 5-LITHIOALKYL-TRIMETHYLSILANEN
Maercker, Adalbert,Eckers, Mechthild,Passlack, Michael
, p. 193 - 205 (1980)
ω-Lithioalkyltrimethylsilanes, prepared from ω-bromoalkyltrimethylsilanes and lithium metal, are fairly stable in diethyl ether as solvent.Upon addition of tetrahydrofuran, however, rearrangements take place, the modes of which are strongly dependent on the number of methylene groups between the lithium and the silicon atoms.With 3-lithiopropyltrimethylsilane an intramolecular 1,5-proton shift with the formation of lithiomethyldimethylpropylsilane is observed.With 4-lithiobutyl-trimethylsilane on the other hand, ring closure to 1,1-dimethylsilacyclopentane takesplace, whereby methyllithium is formed by intramolecular nucleophilic attack on silicon. 5-Lithiopentyltrimethylsilane finally shows ring closure as well as 1,7-proton shift, the ratio depending on the polarity of the solvent.
N-derivatives of 1-deoxy nojirimycin
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, (2008/06/13)
This invention relates to novel N-derivatives of 1-deoxy nojirimycin, to the method for their preparation and to their use in the treatment of diabetes and the use against retro-viruses, particularly in the treatment of acquired immuno-deficiency syndrome
N-derivatives of 1-deoxy nojirimycin
-
, (2008/06/13)
This invention relates to novel N-derivatives of 1-deoxy nojirimycin, to the method for their preparation and to their use in the treatment of diabetes and the use against retro-viruses, particularly in the treatment of acquired immuno-deficiency syndrome
REACTIVITY AND SELECTIVITY IN THE CYCLIZATION OF SILA-5-HEXEN-1-YL CARBON-CENTERED RADICALS
Wilt, James W.
, p. 3979 - 4000 (2007/10/02)
A trio of sila-5-hexen-1-yl radicals has been prepared from the corresponding halides by reaction with tri-n-butyltin hydride (deuteride).The radicals possessing a dimethylsilyl function α or β to the carbon radical center demonstrated marked reduction in total (but especially exo-trig) cyclization compared to the all-carbon system.The γ-silyl radical behaved, contrariwise, quite comparably to the all-carbon system.The difference in cyclization found in the α-silyl radical was demonstrated to result from both a pronounced decrease in cyclization rate via the expected exo-trig mode and from a significantly enhanced rate of hydrogen abstraction from TBTH.Both the α- and γ-silyl radicals cyclized via the endo-trig mode at rates close to that of the parent 5-hexen-1-yl radical itself.The cyclizations studied were demonstrated to be irreversible.The kinetic control thus shown by the preferred formation of endo cyclized product from the α- and β-silyl radicals is highly unusual and represents the first report of carbon-centered 5-hexen-1-yl type radicals violating the Baldwin-Beckwith rule (exo-trig cyclization preferred by 5-hexen 1-yl radicals).Rationalization of the cyclization behavior of the α- and γ-silyl radicals involves both steric and electronic factors.The behavior of the most unusual case, the β-silyl radical, which has the lowest cyclization propensity and no exo mode product, remains largely unexplained because its hydrogen abstraction rate from TBTH is unavailable as yet.Some speculative considerations involving the preferred radical conformation in this system and its relation to cyclization are given.
A Cyclopentanone Annulation via Intramolecular Acylation of Alkylsilanes
Urabe, Hirokazu,Kuwajima, Isao
, p. 1140 - 1141 (2007/10/02)
A facile construction of cyclopentanones is achieved via ring closure of 5-(trimethylsilyl)alkanoyl chlorides under the influence of AlCl3.
