Borodin-Hunsdiecker

Hunsdiecker Reaction (Borodine Reaction, Borodine-Hunsdiecker Reaction)... 

The most useful reaction in the literature for this is the pyrolysis of a suitable per-ester in the presence of a hydrogen atom transfer reagent, but the yields are often unsatisfactory.2 8 Conversion of an acid to the corresponding aldehyde and subsequent rhodium-based decarbonylation involves two steps, but is more reliable.4 The Borodin-Hunsdiecker reaction converts the acid to a nor-halide, which can be reduced by radical methods. However, this works well only with primary acids, is incompatible with many sensitive functions,5 and is expensive since the Ag salt of the acid is usually used. 

Needless to say, this was readily proven to be the case and a variety of chlorides, bromides and iodides have been prepared from the corresponding acids in good to excellent yields, by this method.14,15,26 31 In terms of mildness of conditions, generality and yields, this method is far superior to the classical Borodin-Hunsdiecker reaction and its variants.1011,26"31 As a demonstration of the mildness of the conditions, decarboxyl-ative bromination of the heavily functionalized acid 19 was carried out by Professor Ikegami to afford 20 (75 % yield), and... 

The disodium salt of l-hydroxybenzimidazole-2-carboxylic acid can be decarboxylated merely by heating in acid <88JCS(P1)681>. In a Borodin-Hunsdiecker-type reaction alkaline bromination of 4-... 

The Borodin-Hunsdiecker reaction consists of the reaction of a silver salt of a carboxylic acid with a molecular halogen to give a chain-shortened alkyl halide. 

The phosphonate (327), a phosphorus analogue of desonoic acid, has been synthesized via application of the Borodin-Hunsdiecker reaction to 2-deoxy-o-arabino-hcxose (Scheme 75). ... 

HUNSDIECKER - BORODIN - CRISTOL - FIRTH Decarix)xylation Bromination... 

Substitution of caiboxylic groups by halogen via Ag saHs (Hunsdiecker, Borodin) or Hg salts (Cnstol-Rrth)... 

In some cases we have combined similar reactions under one heading, for instance the Hunsdiecker-Borodin-Cristol-Firth decarboxy-iative bromination. It is not a simple task to decide whether credit is due to... 

Heinz and Clare Hunsdiecker converted Borodin s synthesis into a general method, the Hunsdiecker or Hunsdiecker-Borodin reaction. Borodin was also an accomplished composer and is now best known for his musical masterpiece, opera Prince Egor. He kept a piano outside his laboratory. 

Naskar, D., Chowdhury, S., Roy, S. Is metal necessary in the Hunsdiecker-Borodin reaction Tetrahedron Lett. 1998, 39, 699-702. 

Substitution of carboxylic groups by halogen via Ag salts (Hunsdiecker-Borodin), Hg salts (Cristol-Firth) or Pb salts (Kochi) (see 1st edition). 

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. 

The Hunsdiecker reaction is the reaction of silver carboxylate 1 with bromine to give bromide 2 at elevated temperature.1The reaction also works for making chlorides and iodides. It is also known as the Hunsdiecker-Borodin reaction. 

There are other functional group transformations that lead to alkyl halides. A classical transformation converts carboxylates to allyl bromides (C—CO2 C—Br). This transformation is called the Hunsdiecker reaction (jt jjag also been called the Borodin reaction) 3 and it is most useful for the preparation of econdary halides. The silver salt of a carboxylic acid is heated with bromine to give the bromide via decarboxylation. An example is conversion of the silver salt of cyclohexane carboxylic acid (163) to bromo-cyclohexane.1 4 Phosphorus and bromine also react with acids in the Hell-Volhard-Zelinsky reaction. 

Example 4, One-pot microwave-Hunsdiecker-Borodin followed by Suzuki ... 

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