Cristol-Firth method reaction

Davis et al. found the Cristol-Firth method most satisfactory for carrying out the Hunsdiecker reaction and suggest procedural details for improvement of results. 

In some cases we have combined similar reactions under one heading, for instance, the Hunsdiecker-Borodin-Cristol-Firth decarboxylative bromination. It is not a simple task to decide whether credit is due to the first discoverer of a reaction or to is developer. Often an improvement on a method is more useful than the original discovery, and usually one reaction owes its inception to some previous discovery non nova sed nove. 

Decarboxylation. Della and Patney recommend a two-step method for decarboxylation of bridgehead carboxylic acids. The first step is the Cristol-Firth modification of the Hunsdiecker reaction (I, 657, improved by use of methylene bromide as solvent). The second is photochemical reduction of the bromides by tri- -butyltin hydride (I, 1192-1193) with azobisisobutyronitrile as initiator. Yields are 80-95% in the first step and 80-90% in the second step. 

Tliis procedure, which is a modified Hunsdiecker reaction bused upon the method of Cristol and Firth, results in moderate 1(1 liigli yields of bromides and iodides from aliphatic and alicyclic carboxylic acuds, Carbon tc trachloride is most li cipiciiUy used as the solvent, but others can be einjiloycd. - ... 

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