75142-63-1Relevant academic research and scientific papers
Silicon-catalyzed conversion of nitro compounds into ketones and poly(1,3-diketones)
Hwu, Jih Ru,Josephrajan, Thainashmuthu,Tsay, Shwu-Chen
, p. 3305 - 3308 (2008/09/17)
The reaction of various secondary nitro compounds with 1.1 equivalents of potassium hydride in 1,4-dioxane and then with 0.10 equivalent of chlorotrimethylsilane gave the corresponding ketones in 62-90% yields. By a similar strategy, poly(1,3-diketones) were synthesized directly from nitroalkenes with sodium ethoxide, potassium hydride, and chlorotrimethylsilane in 1,4-dioxane. The use of chlorotrimethylsilane in a catalytic amount was the key to the success of this transformation; the use of an excess of chlorotrimethylsilane led to poor yields for the same reactions. Georg Thieme Verlag Stuttgart.
Intramolecular ene and related reactions, Part 9. Photochemically induced synthesis of allylsilane carbaldehydes
Tietze,Wunsch
, p. 985 - 990 (2007/10/02)
Allylsilane carbaldehydes are valuable substrates for the tandem Koevenagel allylsilane and iminium cyclization. They can easily be prepared by a photochemical α-cleavage of cyclic ketones bearing a trimethylsilylmethyl group in the α-position (Norrish Ty
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.
α-ALKYLATION AND α-ALKYLIDENATION OF CARBONYL COMPOUNDS BY O-SILYLATED ENOLATE PHENYLTHIOALKYLATION
Paterson, Ian
, p. 4207 - 4220 (2007/10/02)
For many reactions next to a carbonyl group, the use of O-silylated enolate chemistry offers improvements in yield and selectivity over the corresponding reactions of Group I metal enolates.In the case of α-alkylation of carbonyl compounds, Lewis acid (TiCl4 or ZnBr2) promoted phenylthioalkylation of O-silylated enolates 3 by α-chlorosulphides 4 (R3=H, Me, Prn, Pri, Bui, and Me3Si), followed by reductive sulphur removal by Raney nickel, 5->6, is found to be a reliable method for this synthetically important C-C bond forming step.An alternative sulphur elimination pathway via the sulphoxide, 5->7, allows the regio- and stereocontrolled α-alkylidenation of carbonyl compounds.The phenylthioalkylation reaction is applicable to ketones, aldehydes, esters, and lactones.
SILICON-DIRECTED BECKMANN FRAGMENTATION
Nishiyama, Hisao,Sakuta, Koji,Osaka, Noriyuki,Arai, Hiroyuki,Matsumoto, Makoto,Itoh, Kenji
, p. 2413 - 2426 (2007/10/02)
The selective fragmentation reactions of β-trimethylsilylketoximes have been proved to proceed effectively with acid catalysts giving the corresponding nitriles.Cyclic silylketoximes gave unsaturated nitriles.The fragmentation in the Beckmann rearrangement is completely controlled and directed by a trimethylsilyl group to lead the regio- and stereo-specific formation of the double bond.The catalytic fragmentation proceeds with the combination of trimethylsilyl ketoxime acetates and trimethylsilyl trifluoromethanesulfonate giving nitriles in high yields.Excellent stereospecificity of the fragmentation based on the stereochemical outcome was discussed.Simple stereo-controlled synthetic approach to some insect pheromones is also described.
SILICON-DIRECTED BECKMANN FRAGMENTATION. CATALYTIC CLEAVAGE OF CYCLIC β-TRIMETHYLSILYLKETOXIME ACETATES WITH TRIMETHYLSILYL TRIFLUOROMETHANESULFONATE
Nishiyama, Hisao,Sakuta, Koji,Osaka, Noriyuki,Itoh, Kenji
, p. 4021 - 4024 (2007/10/02)
Cyclic (E)-β-trimethylsilylketoxime acetates were effectively cleaved by a catalytic action of trimethylsilyl trifluoromethanesulfonate to give the corresponding unsaturated nitriles.The fragmentation in the Beckmann rearrangement is completely controlled
Cycloelimination of β-Silylethyl Sulphoxides: Alkene, Alkyne, and Vinylsilane-forming Reactions
Fleming, Ian,Goldhill, Jon,Perry, David A.
, p. 1563 - 1570 (2007/10/02)
The cycloelimination (1)->(3) of trimethylsilyl sulphenate from a β-silylethyl sulphoxide is slightly faster than the corresponding cycloelimination (2)->(3) of sulphenic acid itself.The former type of reaction can be used to form acetylenes (
Some uses of silicon compounds in organic synthesis
Fleming, Ian
, p. 7 - 13 (2007/10/02)
1.The amount of γ-phenylthioalkylation of silyl dienol ethers is increased when the triphenylsilyl ether is used in place of the trimethylsilyl ether.Phenylthiomethylation is the least γ-selective carbon electrophile of several tried so far. 2.The acid-catalysed reactions of a range of γ-silyl tertiary alcohols cleanly give rearrangement, in which the silyl group controls the outcome.The reactions are similar in several respects to the rearrangements of the corresponding pinacols, except that the silicon controlled reactions are usually cleaner and give higher yields.The reaction is particularly useful for setting up quaternary carbon atoms.
β-Silylcarbonyl Compounds as Masked Enones
Fleming, Ian,Goldhill, Jon
, p. 1493 - 1498 (2007/10/02)
β-Trimethylsilylketones and lactones can be brominated (3)->(4) and desilylbrominated (4)->(5) specifically to place a double bond between the carbonyl group and the β-carbon atom to which the silicon had originally been bound.The silyl group therefore is a base- and acid stable group masking the α,β-unsaturation of enones.Several α-methylene-ketones and -lactones have been prepared in this way.With ketones, the bromination step seems always to introduce bromine mainly or exclusively at the α-position on that side of the ketone on which the β-silyl group is placed, regardless of whether it is more or the less substituted α-position.
