Oxide silver, reaction with diazoketones

Acid chlorides are reacted with diazomethane to yield the diazoketone which upon reaction with silver oxide rearranges to the next higher homolog of the acid. Biphenyl-2-acetic acid is produced in 86% by the method described below [18]. 

Wolff rearrangement. Finding that the Wolff rearrangement of diazoketones with silver oxide and methanol gave erratic, highly variable results, Newman and Beal developed a procedure for carrying out the reaction in homogeneous solution under mild conditions. A solution of diazoacetophenone in methanol was treated at room temperature with a few drops of a filtered solution of 0.004 mole of silver... 

A further study of the use of the Arndt-Eistert reaction in carbohydrate chemistry examined the reactions of the diazoketone (247) (prepared from a-D-glucoisosaccharinic acid), which gave mainly the orthoester (248) and both the ( )- and (Z)-isomers (249) of a 2,3-unsaturated methyl hexonate derivative on treatment with silver oxide in methanol. The 3-C-methylene derivative (248) is a useful precursor of 4-deoxy-3-C-methyl-D-hexoses. 

Preparation of diazoketones and their rearrangements during hydrolysis (method 271) and alcoholysis (method 295) are discussed elsewhere. Ammonolysis of diazoketones leads to amides of acids containing one more carbon atom than the original acyl halide. Halogen atoms may be present in a remote position on an aliphatic chain. The reaction is carried out by heating the diazoketone in alcohol or dioxane solution with aqueous ammonia in the presence of silver oxide or silver nitrate catalysts. Substituted acetanilides are formed when aniline is used in place of ammonia. ... 

This ester is one carbon atom short of the full side chain of grandisol, so an Arndt-Eistert reaction was used to lengthen the chain by one atom. First, the ester was converted into the diazoketone with diazomethane and, then, the Wolff rearrangement was initiated by formation of the carbene with a Amdt-Eistert chain extension of ester silver compound at the Ag(II) oxidation state. 

---