Frankland reaction

Frankland Reaction is the synthesis of hydrocarbons by zinc-alkyl condensation Zn(CH3)2+2R.Br = 2R.CHa+ZnBr2 Ref Hackh s Diet (1944), 355-R... 

WURTZ-FITTIG-FRANKLAND REACTION. Sodium metal was used by Wiirtz as reagent for the preparation of paraffin hydrocarbons... 

These two reactions are known by the names of the men who discovered them. The first one, with zinc, is known as the Frankland Reaction and will be spoken of again (page 76). The second, with sodium, is known as the Wurtz Reaction. 

Synthesis of the Two Butanes.—The two isomeric propyl iodides, by means of the Wurtz and Frankland reactions, yield the two isomeric butanes, the constitution of which must, therefore, be as shown in the following reactions ... 

When zinc acts upon alkyl iodides in the Frankland reaction (p. 16), the final product, is a hydrocarbon composed of two of the alkyl radicals linked together. 

Frankland Reaction or Synthesis.—The discovery of the zinc alkyls was made by Frankland in 1850 and the reactions and syntheses above are known as the Frankland Reaction. 

With water the ethyl magnesium iodide yields the hydrocarbon corresponding to the alkyl radical just as in the Frankland reaction, as follows ... 

These general reactions of the organo-metallic compounds in the Frankland reaction and the Grignard reaction, especially the latter, are applicable with modifications in a great variety of cases, so that by means of them alkyl radicals may be. introduced into various desired positions. A further discussion of these reactions, at this time, is not necessary or desirable in this work, but they will be referred to in connection with certain compounds where they are especially important. 

Other references related to the Frankland reaction are cited in the literature. 

Probably because of unfamiliarity with his early work the name Frankland reaction has not been used although, as has been made clear earlier, many good reasons exist for such a claim. 

For the Frankland reaction the reasoning behind the choice was rather obvious it avoided the tedious and risky reaction-step to prepare ethylzinc. 

This preparation was discovered independently by Geuther (1863) and by Frankland and Duppa (1865). The reaction was subsequently investigated in detail and so w idely extended by Claisen that it has become solely a specific example of the more general process known as the Claisen Condensation. Claisen showed that an ester under the influence of sodium ethoxide would not only condense with itself (as in the preparation of ethyl acetoacetate), but also with (i) another ester, (ii) a ketone, if of formula RCHgCOR, (iii) a nitrile, if of formula RCH CN, in each case with the elimination of alcohol. Examples of these modifications are ... 

Pyrimidin-5-amine, 4-methylamino-synthesis, 3, 121 Pyrimidin-5-amine, 4-oxo-purfne synthesis from, 5, 582 Pyrimidinamines acylation, 3, 85 alkylation, 3, 86 basic pXa, 3, 60-61 diazotization, 3, 85 Dimroth rearrangement, 3, 86 electrophilic reactions, 3, 68 Frankland-Kolbe synthesis, 3, 116 hydrolysis, 3, 84 IR spectra, 3, 64 N NMR, 3, 64 nitration, 3, 69 Principal Synthesis, 3, 129 reactivity, 3, 84-88 structure, 3, 67 synthesis, 3, 129 Pyrimidin-2-amines alkylation, 3, 61, 86 basic pK , 3, 60 diazotization, 3, 85 hydrogenation, 3, 75 hydrolysis, 3, 84 mass spectra, 3, 66 Pyrimidin-4-amines acidity, S, 310 alkylation, 3, 61, 86 basic pXa, 3, 61 Schifi base, 3, 85 synthesis, 3, 110, 114 1,3,5-triazines from, 3, 518 Pyrimidin-5-amines basic pXj, 3, 61 hydrogenation, 3, 75 reactions... 

The direct reaction of zinc metal with organic iodides dates back to the work of Frankland(67). Several modifications have been suggested since that time to increase the reactivity of the metal. The majority of these modifications have employed zinc-copper couples(68-72), sodium-zinc alloys(73), or zinc-silver couples(77). Some recent work has indicated that certain zinc-copper couples will react with alkyl bromides to give modest yields of dialkylzinc compounds(74,73). However, all attempts to react zinc with aryl iodides or bromides have met with failure. The primary use of zinc couples has been in the Simmons-Smith reaction. This reaction has been primarily used with diiodomethane as 1,1-dibromides or longer chain diiodides have proven to be too unneactive even with the most reactive zinc couples. 

If a stream of hydrogen issues into air and a light is applied to it, it burns (in accordance with the above equation) with an almost non-luminous flame (This reaction is, of course, reversible, i.e. a stream of air would burn in the same way in an atmosphere of hydrogen.) It was discovered by Frankland that while at atmospheric pressure the flame of hydrogen burning in oxygen is almost non-luminous if the pressure is... 

Frankland s method orgchem Reaction of dialkyl zinc compounds with alkyl halides to form hydrocarbons may be used to form paraffins containing a quaternary carbon atom. frarik-lonz, meth-3d ... 

Until fairly recently, little was known of the stmcmres and properties of the organozinc compounds occurring as intermediates in varions reactions. Interestingly, the complexforming ability of organozinc componnds had already been recognized very early. In 1858, Wanklyn reported the formation of the ionic sodium triethylzinc complex. One year later, Frankland observed that the formation of dimethylzinc from methyl iodide and zinc was accelerated by the addition of dimethyl ether or diethyl ether. It appeared that separation of the dimethylzinc from the ether was impossible, bnt it lasted nntil 1962 when it was established that dimethylzinc and dimethyl ether form a 1 1 complex in solntion, which is appreciably dissociated in the vaponr phase. ... 

The study of the structure of molecules was originally carried on by chemists using methods of investigation that were essentially chemical in nature, relating to the chemical composition of substances, the existence of isomers, the nature of the chemical reactions in which a substance takes part, and so on. From the consideration of facts of this kind Frankland, Kekul6, Couper, and Butlerov1 were led a century ago to formulate the theory of valence and to write the first structural... 

Frankland introduced the use of zinc instead of sodium to accomplish similar reactions. See also Fitting Reaction and Organic Chemistry,... 

Reaction XLI3I. (d) Condensation of Diethyl Oxalate with Alkyl Halides in the presence of Zinc (Frankland- -Duppa). (A., 185, 184.)—This is a type of condensation very similar to those just described. The zinc alkyl is not isolated, and simple halogen compounds are used. The product is a derivative of glycollic acid. 

About the same time Frankland and Duppa, using the same reaction, discovered that the hydrogen atoms of the methylene group are replaceable by sodium and various organic radicles. 

Wislicenus next showed that the product under discussion was acetoacetic ester and that two hydrogen atoms were replaceable by sodium in two stages. He represented the reactions in the following manner, adopting the formula of Frankland ... 

In 1853, E. Frankland made the first synthetic organomercury compound by the photochemical reaction below ... 

It is interesting that Walden s work (Ingold, 1953) on substitution reactions and Michael s work on addition-elimination appeared at the same time. By 1912, Frankland could sense that trans processes and the Walden inversion (equations 4b, d) were related, and an underlying explanation would eventually be found for both. 

The possibility that reacting species prefer to react along those paths in which they undergo the least modification has always been intuitively attractive. At one time or another, so-called principles of minimum structural change or deformation, configurational change, and minimum atomic and electronic motion have been invoked (Wheland, 1960 Hine, 1966). To account for Michael s rule of favored anti 1,2-addition, Pfeiffer formulated acetylenes as tram-heat structures in 1904 Frankland (1912) suggested that anti elimination is favored by an inherent tendency to centric symmetry. The more conscious applications of PLM by Muller after 1886, are probably misapplications of the principle, since they were usually concerned with complex pyrolytic reactions above 1000° (Muller and Peytral, 1924). 

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