Carbon target preparation

The synthesis was very short, requiring only ten steps, six of which were C-C bond-forming steps, to prepare the twenty-carbon target 1. 

Radiocarbon age for which the signal is equal to measured background for FOaC target prepared from carbon dioxide 40,000 years... 

Abstract. Thermally-assisted grafting of linear alkene molecules either in the liquid phase (ethyl undecylenate) or in the gas phase (perfluorodecene), has been performed on atomically flat amorphous carbon (a-C) films with variable average surface hybridization, sp3/(sp2+ sp3), as obtained from X-ray photoelectron spectroscopy. In contrast with the sp2-rich sputtered a-C, optimized sp3-rich a-C films obtained by Pulsed Laser ablation of a glassy carbon target do not require surface preparation before hquid phase grafting. 

Begin by asking the question What kind of compound is the target molecule and what methods can I use to prepare that kind of compound The desired product has a bromine and a hydroxyl on adjacent carbons it is a vicinal bromohydrin The only method we have learned so far for the preparation of vicinal bromohydrms involves the reaction of alkenes with Bi2 m water Thus a reasonable last step is... 

Lithium Oxide. Lithium oxide [12057-24-8], Li20, can be prepared by heating very pure lithium hydroxide to about 800°C under vacuum or by thermal decomposition of the peroxide (67). Lithium oxide is very reactive with carbon dioxide or water. It has been considered as a potential high temperature neutron target for tritium production (68). 

Hoffmaim-La Roche has produced -carotene since the 1950s and has rehed on core knowledge of vitamin A chemistry for the synthesis of this target. In this approach, a five-carbon homologation of vitamin A aldehyde (19) is accompHshed by successive acetalizations and enol ether condensations to prepare the aldehyde (46). Metal acetyUde coupling with two molecules of aldehyde (46) completes constmction of the C q carbon framework. Selective reduction of the internal triple bond of (47) is followed by dehydration and thermal isomerization to yield -carotene (21) (Fig. 10). 

The Corey-Winter reaction provides a useful method for the preparation of olefins that are not accessible by other routes. For instance it may be used for the synthesis of sterically crowded targets, since the initial attack of phosphorus at the sulfur takes place quite distantly from sterically demanding groups that might be present in the substrate molecule. Moreover the required vicinal diols are easily accessible, e.g. by the carbon-carbon bond forming acyloin ester condensation followed by a reductive step. By such a route the twistene 10 has been synthesized ... 

A ketone vvith a substituent group in its /3 position might be prepared by a conjugate addition of that group to an a,/3-unsaturated ketone. In the present instance, the target molecule has a propyl substituent on the /3 carbon and might therefore be prepared from 2-methyl-2-cyclopentenoneby reaction with lithium dipropylcopper. 

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