Synthesis of adamantane derivatives. 61. Convenient generation of adamantylidenecarbene from (bromomethylene)adamantane. An efficient method of adamantylidenecyclopropanation
Unusual behaviour of 2-methyladamantane during bromination
作者:J. R. Alford、D. Grant、M. A. McKervey
DOI:10.1039/j39710000880
日期:——
cis- and trans-1-bromo-4-methyladamantane the expected products of bridgehead substitution, bromination of 2-methyladamantane with hot bromine gives 4eq- and 4ax-bromo-2-(dibromomethylene)adamantane. The monobromides were not isolated as such, but were hydrolysed to the corresponding alcohols. The tribromides may be formed by an ionic mechanism involving an adamantane–protoadamantane–adamantane rearrangement
Radical cation chain oxygenation of dienes by triplet oxygen
作者:Stephen F. Nelsen、Mark F. Teasley、Daniel L. Kapp
DOI:10.1021/ja00278a022
日期:1986.9
Alkylated 1,3-dienes are shown to oxygenate to endoperoxides by a cation radical chain mechanism. Steric slowing of Diels-Alder dimerization appears to be necessary; 1,3-cyclohexadiene gave only dimer under conditions where its 1-isopropyl-4-methyl derivative gave a 96% yield of ascaridole. The cation radical chain conditions tolerate more steric crowding than does the singlet oxygen reaction, as 4,4'-bihomoadamantenyl
Kostikov, R. R.; Grishina, E. N.; Slobodin, Ya. M., Journal of Organic Chemistry USSR (English Translation), 1984, vol. 20, p. 1298 - 1306
作者:Kostikov, R. R.、Grishina, E. N.、Slobodin, Ya. M.
DOI:——
日期:——
Preparation and carbon 13 NMR spectroscopic study of the 2-(adamantylidenemethyl)-2-adamantyl and 2-adamantylidene-1,1-dicyclopropylethyl cations
作者:George A. Olah、V. Prakash Reddy、Joseph Casanova、G. K. Surya Prakash
DOI:10.1021/jo00050a014
日期:1992.11
2-(Adamantylidenemethyl)-2-adamantyl cation (5) was prepared by ionization of 2-(adamantylidenemethyl)-2-adamantanol (9) in FSO3H/SO2ClF or neat FSO3H at -78-degrees-C. In spite of its high inherent steric strain, carbocation 5 is stable up to 80-degrees-C. Its rotational barrier was estimated to be 16.8 kcal/mol on the basis of the coalescence temperature of the C-13 NMR signals of its diastereomeric beta-methylene carbons, which is in agreement with a DELTAH(double dagger) value of 16.5 kcal/mol calculated by MNDO. Similarly, 2-adamantylidene-l,l-dicyclopropylethyl cation (6) was prepared by the ionization of 1,1-dicyclopropyl-2-(2-hydroxy-2-adamantyl)ethanol (12) in SbF5-FSO/SO2ClF or FSO3H/SO2ClF. Carbocation 6 shows a rotational barrier of less than 5 kcal/mol. The small rotational barrier in 6 is interpreted as due to the positive charge stabilizing influence of the adjacent cyclopropyl groups resulting in an unsymmetrically charge-delocalized allylic cation.
Ruasse, M. F.; Motallebi, S., Bulletin de la Societe Chimique de France, 1988, # 2, p. 349 - 355