- Metal-free tetrahydrofuranylation of alcohols with tertbutyl nitrite
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Metal-free tetrahydrofuranylation of alcohols in the presence of tertbutyl nitrite is described, providing a facile and green route for the protection of hydroxy groups. Mechanistic studies demonstrate that this transformation proceeds in a radical way, and involves alkyl nitrite of corresponding alcohol as the key intermediate.
- Bi, Kang,Cai, Yue-Ming,Lin, Junyue,Liu, Miao-Chang,Zhou, Yun-Bing
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supporting information
(2020/08/06)
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- Novel and highly selective conversion of alcohols and thiols to alkyl nitrites with triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone/Bu 4NNO2 system
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Alkyl nitrites were prepared in good to excellent yields by treatment of alcohols and thiols with triphenylphosphine/2,3-dichloro-5,6- dicyanobenzoquinone/Bu4NNO2 in acetonitrile. This method is highly selective for the conversion of primary alcohols to alkyl nitrites in the presence of secondary and tertiary alcohols and thiols.
- Akhlaghinia, Batool,Pourali, Ali Reza
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p. 1747 - 1749
(2007/10/03)
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- Oxidation of benzylic alcohols and ethers to carbonyl derivatives by nitric acid in dichloromethane
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Nitric acid in dichloromethane may be successfully employed for the oxidation of benzylic alcohols and ethers to the corresponding carbonyl compounds. The proposed method proved to be of general applicability, affording very good yields of aldehydes and ketones and showing interesting chemoselectivity in many instances, allowing competitive aromatic nitration to be avoided, as well as - in the case of aldehydes - any further oxidation to carboxylic acids. The reaction probably proceeds by a radical mechanism, the active species in the oxidation process being NO2. Competitive formation of nitro esters was observed in some cases, whereas poor results were obtained with allylic and non-benzylic substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Strazzolini, Paolo,Runcio, Antonio
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p. 526 - 536
(2007/10/03)
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- Cyclodextrin catalysis in the basic hydrolysis of alkyl nitrites
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The influence of β-cyclodextrin (β-CD) on the hydrolysis reaction of a variety of structural types of alkyl nitrites (RONO) is studied in acid and in basic aqueous solutions.Acid-catalysed hydrolysis of alkyl nitrites is inhibited by the presence of β-cyclodextrin.The results are accounted for by assuming the formation of host-guest complexes between β-cyclodextrin and alkyl nitrite, which are unreactive or much less reactive than the uncomplexed RONO.We propose that the result is a concenquence of the orientation of alkyl nitrite in the cavity of CD.The degree of inhibition increases with the greater inclusion of the alkyl nitrite in the CD cavity.The kinetic data are quantitatively analyzed to afford the stability constants of the host-guest complexes.On the contrary, the presence of β-cyclodextrin strongly increases the rate of hydrolysis of alkyl nitrites in a basic medium, that is at a pH value higher than the pKa of β-cyclodextrin.This feature suggests the formation of a reactive complex between the alkyl nitrite and β-cyclodextrin, whose ionized CD hydroxy group promotes a nucleophilic attack in the rate-limiting step.This behaviour is consistent with a higher reactivity towards alkyl nitrites of an ionized CD hydroxy groups as compared with the OH-; the contrary occurs in the case of esters, whose cleavage by cyclodextrin in basic aqueous media has been studied extensively over the last several years.
- Iglesias, Emilia,Fernandez, Aurora
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p. 1691 - 1700
(2007/10/03)
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