Carbonates without additional anions, with

C Carbonates without additional anions, with H2O 5.CA. With medium-sized cations... 

A Carbonates without additional anions, without H2O 5. A A. Alkali carbonates 5.AB. Alkali-earth (and other carbonates 5.AC. Alkali and alkali-earth carbonates 5.AD. With rare-earth elements (REE)... 

Isolated carbon-carbon double bonds are not normally reduced by dissolving metal reducing agents. Reduction is possible when the double bond is conjugated, because the intermediate anion can be stabilized by electron delocalization. The best reagent is a solution of an alkali metal in liquid ammonia, with or without addition of an alcohol - the so-called Birch reduction conditions. Under these conditions conjugated alkenes, a,p-unsaturated ketones and even aromatic rings can be reduced to dihydro derivatives. 

There is an example of alkaloid-induced asymmetric reactions in an IL medium. Dimethyl malonate reacted with chalcone under the action of potassium carbonate in the presence of quininium-derived phase transfer catalyst (PTC) 27 in a [bmim] [PFg] melt to give adduct 28 in high yield but with a slightly lower enantioselectivity than in conventional organic solvents (DMSO or toluene) (Scheme 22.10) [49]. Most surprisingly, the absolute configuration of product 28 reversed in the IL medium. Additional experiments with quinine or N-(4-nitrobenzyl)quininium bromide as PTC indicated that the reversal of enantioselectivity was not due to the PTC but can be attributed to the cation associated with the anion of the ionic liquid. The process was successfully repeated in the presence of the recovered IL/PTC system without a reduction in reaction rate or product yield. 

This novel electroreductive cyclocoupling corresponds to a 1,4-addition of a one-carbon unit to the 1,3-diene, and does not take place without using magnesium electrode. The first step in this coupling reaction is the cathodic reduction of 1,3-diene to an anion radical, and the second step is the formation of a Mg-diene complex, which thereafter reacts with the ester to yield the coupling product as shown in equation 23b. 

The temp. coeS. of the eq. conductivity of sodium carbonate soln. for the mean temp. 22° is 00265 and for potassium carbonate, 0-0249. H. C. Jones and A. P. West, and C. Deguisne have also studied the temp, coeff. of the conductivity of these salts. M. H. van Laar studied the formation of sodium hydroxide by the electrolysis of soln. of sodium carbonate with and without the addition of an oxy-salt. W. Bien calculates the transport number for the anion in 0 052V-soln. at 23° to be 0 590, but as in the case of lithium carbonate hydrolysis interferes with the... 

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