53140-72-0Relevant academic research and scientific papers
Enhanced enantio- and diastereoselectivity via confinement and cation binding: Yang photocyclization of 2-benzoyladamantane derivatives within zeolites
Natarajan, Arunkumar,Joy, Abraham,Kaanumalle, Lakshmi S.,Scheffer, John R.,Ramamurthy
, p. 8339 - 8350 (2007/10/03)
Irradiation of 2-benzoyladamantane derivatives in zeolites yields the endo-cyclobutanols as the only photoproduct via a γ-hydrogen abstraction process. The cyclobutanols readily undergo retroaldol reaction to give δ-ketoesters. The enantiomeric excess (ee) in the endo-cyclobutanols is measured by monitoring the ee in the ketoesters. Whereas in solution the ee in the product ketoester is zero, within achiral NaY zeolite, in the presence of a chiral inductor such as pseudoephedrine, ee's up to 28% have been obtained. The influence of zeolite on several chiral esters of 2-benzoyladamantane-2-carboxylic acids has also been examined. Whereas in solution the diastereomeric excess is 15%, in zeolite the δ-ketoesters are obtained in 79% de (best examples). Ab initio computations suggest that enhancement of chiral induction within zeolites is likely to be due to cation complexation with the reactant ketone. Alkali ion-organic interaction, a powerful tool, is waiting to be fully exploited in photochemical and thermal reactions. In this context zeolites could be a useful medium as one could view them as a reservoir of "naked" alkali ions that are only partially coordinated to the zeolite walls.
Facial selectivity in the addition of nucleophiles to the radical cations of substituted 2-methyleneadamantanes
Swansburg,Janz,Jocys,Pincock,Pincock
, p. 35 - 47 (2007/10/03)
The diphenylmethylenecyclohexane, 2, and the substituted 2-methyleneadamantanes, 3-7, have been prepared. The radical cation of each was generated by photochemical oxidation using 1,4-dicyanobenzene as the sensitizer, and their reactivity was examined in
Face Selection in the Capture of Anionic Carbon
Bodepudi, Vani R.,Noble, William J. le
, p. 3265 - 3269 (2007/10/02)
Several reactions of 2-(5-phenyladamantyl) derivatives have been examined with the objective of determining the stereochemistry of addition of electrophiles to a trigonal center C2 carrying a full or partial negative charge.These reactions included the ca
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.
