- Exhaustive One-Step Bridgehead Methylation of Adamantane Derivatives with Tetramethylsilane
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A methylation protocol of adamantane derivatives was investigated and optimized using AlCl3 and tetramethylsilane as the methylation agent. Substrates underwent exhaustive methylation of all available bridgehead positions with yields ranging from 62 to 86 %, and up to six methyl groups introduced in one step. Scaling-up of the reaction was demonstrated by performing the >40 gram-scale synthesis of 1,3,5,7-tetramethyladamantane with 62 % yield. For several substrates, rearrangements were observed, as well as cleavage of functional groups or Csp3?Csp2 bonds or even cyclohexyl-adamantyl bonds. Based on mechanistic studies, it is suggested that a reactive methylation complex is formed from tetramethylsilane and AlCl3. X-ray diffraction structures of hexamethylated bis-adamantyls reveal elongation or widening of sp3 carbon bonds between adamantyl moieties to 1.585(3) ? and 125.26(9)° due to repulsive H???H contacts.
- Bonsir, Maxime,Davila, Christian,Geerts, Yves,Kennedy, Alan R.
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p. 5227 - 5237
(2021/10/19)
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- Contribution a l'etude des reactions d'alkylation et de polyalkylation de l'adamantane et de ses homologues
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A method for preparing alkyl derivatives of cage-structure compounds is proposed.It relies on the use of Grignard reactions with a high boiling point solvent.The reactions take place at atmospheric pressure.Methylation of adamantane, diamantane, and homoadamantane occurs with quantitative yield.With other primary alkyl groups, yields are better than 60percent.Competition between alkylation and secondary reactions is discussed on the basis of a free radical mechanism.
- Molle, G.,Dubois, J. E.,Bauer, P.
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p. 2428 - 2433
(2007/10/02)
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- REACTION OF 1-ADAMANTANOL WITH α-OLEFINS IN TRIFLUOROACETIC ACID
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In the reaction of 1-adamantanol with α-olefins (CH2=CHR) in the presence of trifluoroacetic acid the main reaction products are 1-(1-adamantyl)1-alkanols, and the side products are the isomeric alcohols and alkenyladamantanes.In the reaction of 1-adamantanol with 1,5-hexadiene selective reaction occurs between the initial alcohol and only one double bond of the diene; adamantylated hydrocarbons are mainly formed as a result of the reaction.The reaction of 1-adamantanol with α-olefins in trifluoroacetic acid can be used as a preparative method for the production of hydroxyalkyladamantanes.
- Kovalev, V. A.,Shokova,E. A.
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