Acetic acid, diazoesters synthesis

Thallium(m) acetate effects a one-step synthesis of aliphatic a-acyloxy-carboxylic acids (Scheme 28) the transition state (92) is proposed. a-Aminoesters are readily oxidized to the corresponding a-diazoesters by isoamyl nitrite in the presence of acetic acid. A review has been published on the radical addition of carboxylic acids and derivatives to unsaturated linkages. ... 

Lewis acids efficiently catalyze the transfer of diazoketones and diazoesters to amides and nitriles to furnish 2,4,5-trisubstimted oxazoles (Scheme 1.49). In particular, Eguchi and co-workers found that BF3 OEt2 was the best catalyst for reaction of the adamantyl diazoketoester 180 with acetonitrile. Attempts to prepare 181 using Rh(II)acetate or photolysis were unsuccessful. Similarly, Ibata and Isogami °° described a general synthesis of 5-aryl-2-(chloromethyl)oxazoles 183 from a BF3.0Et2-catalyzed addition of a-diazoacetophenones 182 with chloro-acetonitrile. The yields were quite respectable (Table 1.12). 

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