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Silyl enol ethers reaction with nitro olefins

The illustrative example is the synthesis of heptane-2,5-dione (Expt 5.105). A related reaction is the interaction of a silyl enol ether, derived from a ketone, with a nitro olefin in the presence of either titanium(iv) chloride or... [Pg.635]

In the early 1960s, Brannock et al. reported a thermal [2+2] cycloaddition of enamines. Enamines react with a variety of electron-deficient alkenes such as acrylates, nitro-olefines, acetonitriles, vinylsulfones, fumarates, and malei-mides to give aminocyclobutanes [4]. The reaction generally does not require the assistance of an acid catalyst. Narasaka et al. exploited asymmetric thermal [2+2] cycloaddition of vinyl and aUenyl sulfides with electron-deficient alkenes catalyzed by Lewis acid [5]. Yamazaki et al. have reported that a stoichiometric amount of Lewis acid activates [2+2] cycloaddition of vinylselenides with highly electron-deficient olefins [6]. These reactions proceed via a stepwise annulation to give mercapto- and seleno-cyclobutanes, respectively. However, cyclobutane formation from silyl enol ethers, which are one of the most easily prepared ketone... [Pg.115]

Synthesis of Keto-acids.—a-Keto-acids are obtained in moderate to good yields by the reaction of carboxylic acid dianions with conjugated nitro-olefins at — 100°C, followed by acidic work-up. Another route to these compounds involves the C-silylation of butyrolactone enolate, followed by a Peterson-type olefination to give the vinylic ether (20), which is then oxidized to the y-keto-acid (Scheme 12). Eight examples, with yields of between 50 and 83%, along with one failure are reported. [Pg.100]

As the accompanying equations illustrate, the reactions of enol silyl ethers are regarded as those of either electron-rich olefins or stable metal enolates. The treatments of eno/ silyl ethers with halogens, NBS, sulfenyl halides, and nitronium ions afford the corresponding a-halo, alkylthio, and nitro ketones, respectively (eq (22)) [19]. [Pg.396]


See other pages where Silyl enol ethers reaction with nitro olefins is mentioned: [Pg.126]   
See also in sourсe #XX -- [ Pg.635 ]




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Enolates silylation

Enolates, silyl reactions

Enols reactions with

Nitro enolate

Olefin reactions

Olefination reactions

Reaction with enol silyl ethers

Reaction with ethers

Reaction with olefins

Reactions, with enol ethers

Reactions, with enolates

Silyl enol ethers

Silyl enol ethers reaction

Silyl enolate

Silyl enolates

Silyl ethers reaction with

Silyl ethers reactions

Silyl reactions with

Silylation reactions

Silyls reactions with

With Olefins

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