Potassium tert-butoxide in synthesis

Pearson, D. E.; Buehler, C. A.

doi:10.1021/cr60287a004

Cited by 114 publications

(35 citation statements)

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“…Activation of the remaining secondary alcohol as the tosylate 25 followed by elimination using tBuOK in hexane gave the required alkene 26 with a high degree of regioselectivity (14:1). [28] During a solvent screen for this reaction, we observed that nonpolar solvents gave the best selectivity, despite the low solubility of the base.…”

Section: Entries 1 3 and 4)mentioning

confidence: 96%

Diastereodivergent Synthesis of Trisubstituted Alkenes through Protodeboronation of Allylic Boronic Esters: Application to the Synthesis of the Californian Red Scale Beetle Pheromone

Hesse

Butts²,

Willis³

et al. 2012

Angew Chem Int Ed

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Section: Entries 1 3 and 4)mentioning

confidence: 96%

Diastereodivergent Synthesis of Trisubstituted Alkenes through Protodeboronation of Allylic Boronic Esters: Application to the Synthesis of the Californian Red Scale Beetle Pheromone

Hesse

Butts²,

Willis³

et al. 2012

Angew Chem Int Ed

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“…Our results disagree with those noted by Pearson and Buehler. 18 We succeeded in dissolving MeOK in toluene in the presence of [222], thus making possible a homogeneous initiation in the field of anionic polymerization.…”

Section: Solubilities Of the Metal Alkoxides In The Absencementioning

confidence: 99%

Homogeneous Polymerization of Methyl Methacrylate Initiated by Potassium Salts of Methanol and t-Butyl Alcohol in the Presence of Cryptand [222]

Viguier

Collet

Schué

1982

Polym J

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ABSTRACT:Homogeneous polymerization of methyl methacrylate initiated by potassium salts of methanol and t-butyl alcohol was studied in toluene in the presence of cryptand [222). The polymers prepared were predominantly syndiotactic. The isotacticities increased slightly with an increase in temperature. More than thirty years ago, it was claimed that alkali metal salts of primary alcohols could not initiate the polymerization of methyl methacrylate (MMA) in ether.' More recently, the oligomerization of MMA by CH 3 0-jCH 3 0H solutions has been studied.Z· 3 Oligomers having a degree of polymerization up to six were isolated and characterized. Initiation proceeded by the addition of CH 3 0-to the double bond, and termination by protonation from the methanol.t-Alkoxides, n-butoxides, derivatives of poly(ethylene oxide) of alkali metals as well as ethylmagnesium alkoxides for the initiation of the homogeneous polymerization of methacrylic acid esters have been described in previous papers. 4 -10 It has also been shown that the polymerization of MMA by alkali metal salts of 2-methoxyethanol and like compounds can be carried out in aprotic dipolar solvents such as hexamethylphosphoramide, dimethyl sulfoxide, and dimethylacetamide." Polymerization was greatly promoted by these solvents, even when in small quantities. It is also well known that cryptands such as (I) complex cationic species very strongly and hence promote nucleophilic reactionsY Several studies on the polymerization using such complexing agents have been reported. 13 _,In this paper, we report on the homogeneous polymerization of MMA in toluene by potassium salts of methanol and t-butyl alcohol in the presence of cryptand (1). It was accepted, according to our previous communication, 17 that such complexing agents increase the reactivity of the alkoxide. (Potassium methoxide and t-butoxide are noted respectively MeOK and t-BuOK.) EXPERIMENTAL MaterialsThe purification of toluene and MMA as well as the experimental techniques are described elsewhere.17 Potassium salts of the alcohols were prepared by the reaction of potassium metal with an excess of alcohol in toluene followed by removing solvent and alcohol under vacuum at 100°C during at least 15 hours. This gave the alkoxides as snow-137

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“…According to the previous reports and above results, a radical-chain reaction mechanism is proposed (Scheme 3). [31][32][33] An aryl halide radical anion is generated from ArÀX by SET in the presence of 1,10-phenanthroline/ KOtBu and converted into an aryl radical upon elimination of X À . The aryl radical reacts with CO to afford an acyl radical, which further reacts with tBuO À to give the ester radical anion.…”

mentioning

confidence: 99%