29542-62-9Relevant articles and documents
Thermolysis of Highly Congested Tri-tert-alkylmethanes. Rearrangement of a 3-Noradamantylmethyl Radical
Lomas, John S.
, p. 519 - 528 (2007/10/02)
Activation energies for C-Ad fission in the thermolysis of di-1-adamantyl-tert-alkylmethanes and 1-adamantyl-di-1-bicyclooctylmethane, AdR1R2CH, in toluene are best correlated with the strain energy difference (MMP2 force field) between the methane and the corresponding radical, R1R2C radical H; difficulties were encountered in the application of MM3 to certain of these trialkylmethanes.Normally, the major thermolysis product is the di-tert-alkylmethane, R1R2CH2, but when a 3-noradamantly group is present (1d) the initially formed radical ring opens to give 1,2'-biadamantyl in amounts which depend on the temperature and the solvent (normal or octadeuteriated).This rearrangement is readily explained by MMP2 calculations.Since the cross-product yield is low (less than 3percent, even in deuteriated solvent at the highest temperature) the thermodynamic parameters for the hydrogen transfer and ring opening reactions of the 1-adamantyl-3-noradamantylmethyl radical can be compared directly.Both the activation enthalpy and entropy are much greater for ring opening than for hydrogen abstraction from the solvent.Isotope effects on hydrogen abstraction are high and satisfy certain criteria for tunnelling, as do data on the analogous reaction of Ad2C radical H.A more sophisticated treatment of the product composition for 1d thermolysis, using kinetic simulation, leads to essentially the same conclusions as the simpler treatment.
REACTION OF ORGANOMAGNESIUM COMPOUNDS OF THE ADAMANTANE SERIES WITH CARBONYL COMPOUNDS
Yurchenko, A. G.,Fedorenko, T. V.
, p. 875 - 880 (2007/10/02)
In the transformations of organomagnesium compounds of the adamantane series involving aldehydes, ketones, esters, and acid chlorides the nature of the reaction products and their yields are determined by the steric hindrances at the reaction centers of the organomagnesium and carbonyl compounds and by the ease of homolysis of the C-H bonds of the carbonyl reagent.The retardation of the faster addition of the Grignard reagent at the carbonyl group as a result of steric hindrances permits homolytic removal of a hydrogen atom from the carbonyl compounds by the adamantyl radical.
High-Yield Direct Synthesis of a New Class of Tertiary Organolithium Derivatives of Polycyclic Hydrocarbons
Molle, G.,Bauer, P.,Dubois, J. E.
, p. 2975 - 2981 (2007/10/02)
For the first time, 1- and 2-adamantyllithium, 1-diamantyllithium, 3,5,7-trimethyl-1-adamantyllithium, 1-twistyllithium, 3-methyl-7-noradamantyllithium, 1-triptycyllithium, and 3-homoadamantyllithium have been directly synthesized from the reaction of an organic halide and lithium metal.By use of certain experimental parameters, the phenomena at the metal-solution interface are controlled, thereby resulting in exceptionally high yields of this new class of organometallic compounds (>75percent, except in the case of 3-homoadamantyllithium).Competition between formation of the organometallic compound and formation of solvent-attack byproducts is determined by the degree of adsorption of the transient species (anion radical RX-. or radical pair R..Li) generated at the metal surface during attack by the halogenated derivative.
Formation of Cage-Structure Organomagnesium Compounds. Influence of the Degree of Adsorption of the Transient Species at the Metal Surface
Molle, G.,Bauer, P.,Dubois, J. E.
, p. 4120 - 4128 (2007/10/02)
Secondary and tertiary adamantyl organomagnesium compounds have been synthesized with yields of ca. 60percent by means of an original static procedure.By condensing Grignard reagents of adamantane over benzaldehyde, 70percent and 72percent yields of alcohol are obtained; the 1- and 2-adamantanecarboxylic acid chlorides give 40percent and 50percent yields of 1,1- and 2,2-diadamantyl ketone, respectively.Competition between the various reactions occuring either at the metal-solution interface (formation of the organomagnesium compound and of the dimerization hydrocarbon) or in the medium (formation of the solvent-attack products) is studied in terms of the stirring, the nature of the halogen, the basicity of the solvent, and the ratio of the magnesium surface to the halide.The kinetic study of the formation of these organomagnesium compounds demonstrates the essential role of the anion radical (RX) and of radical pair (RMgX), whose degrees of adsorption at the metal surface, i.e., electrostatic interaction between the transient species at the metal surface, after the single electron transfer (SET), determine the competition between the various reaction pathways.These degrees of adsorption are highly dependent on the nature of the cage structure of the radical.An XPS analysis at different depths of the deposit at the metal surface provides invaluable information on the phenomena occuring at the metal-solution interface when 1-bromoadamantane attacks the magnesium.This makes it possible to retrace the history of the reaction in its initial phase.
