1905-16-4Relevant academic research and scientific papers
Regioselectivity on electroreductive transannular reaction of 7-methylenebicyclo[3.3.1]nonan-3-one
Itoh,Kato,Unoura,Senda
, p. 339 - 345 (2007/10/03)
A competitive transannular reaction occurred to give 7-methyltricyclo[3.3.1.03.7]nonan-3-ol (5) and 1-adamantanol (6) in the non-mediated electroreduction of 7-methylenebicyclo[3.3.1]nonan-3-one (1) in N,N-dimethylformamide. The apparent temperature dependence of the regioselectivity of the reaction may be attributed to the competitive operation of both kinetic and thermodynamic controls in the cyclization of the ketyl radical anion. The differences in the parameter of activation between the 5-exo- and 6-endocyclizations of 1,? ,ΔΔH?(5-exo - 6-endo) and ΔΔS?(5-exo - 6-endo), were evaluated to be -3.1 kcal mol-1 and -11 cal mol-1 K-1, respectively. Semiempirical PM3 (RHF and UHF) calculations were also carried out to elucidate the reaction mechanism.
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.
The Barbier Synthesis: A One-Step Grignard Reaction?
Molle, Gerard,Bauer, Pierre
, p. 3481 - 3487 (2007/10/02)
Counter to generally accepted theory, it is demonstrated that the Byrbier synthesis does not necessarily involve the in situ formation of an organometallic compound.In certain cases, there is a radical pathway in which the anion radical (R.-X-) resulting from the attack by a halogenated derivative on lithium is directly trapped by the ketone or by the ketyl radical on the metal surface befor the organometallic compound forms.This pathway can be unique, as when 1-bromoadamantane condenses with adamantanone or hexamethylacetone.However, by extension of the Barbier synthesis to other "cage-structure" compounds homologous to adamantane, it is seen that the radical pathway can compete with the organometallic pathway and that this competition is principally determined by the stability of the cage radicals generated at the metal-solution interface.An optimum yield can be attained in this type of synthesis by choosing the Grignard reaction or the Barbier reaction, depending on the nature of the halogenated cage derivatives in use.
