The Cleavage of Non‐Enolizable Ketones with Sodium Amide. TheHaller‐Bauer Reaction

Abstract

In this chapter the Haller‐Bauer is defined as the action of sodium amide on a non‐enolizable ketone causing cleavage of a carbon‐to‐carbon bond and resulting in the formation of an amide and a hydrocarbon. Textbook definitions have limited the reaction to the alkylation of ketones in which sodium amide acts a condensing agent or have considered it a combination of the alkylation and cleavage reactions. Haller and Bauer reported the isolation of benzamide after the treatment of benzophenone with sodium amide in boiling benzene or toluene and followed this observation with an extended study of the reaction. A modification of the Haller‐Bauer reaction involving the use of a fused eutectic mixture of sodium an potassium amides has been applied to certain alicyclic and bicyclic terpenoid ketones as well as to some amides.

Mechanism of Cu-Catalyzed Aerobic C(CO)–CH3 Bond Cleavage: A Combined Computational and Experimental Study

“…By contrast, the C­(CO)–C bond cleavage of ketone is more challenging because of the competitive reactions of carbonyl group and C α –H bonds, and also the strong nucleophilicity of carbanion during heterolytic bond cleavage. Although the traditional haloform reaction, Baeyer–Villiger reaction, Schmidt reaction, and Haller–Bauer reaction are capable of cleaving C­(CO)–C bonds, the limited scopes of products and functional-group-tolerance is still motivating the exploration of new methods. Some emerging transition-metal-catalyzed reactions have enriched C­(CO)–C bond activation/functionalization reactions by utilizing chelating groups or relatively active ketones like strained ketones, 1,2- and 1,3-diketones, α-ketoacid .…”

Polymer-supported syntheses of thiophene-containing compounds using a new type of traceless linker

“…35 This cleavage reaction is clearly closely related to the classical Haller-Bauer reaction which typically uses a suspension of sodamide in a high boiling hydrocarbon solvent to cleave non-enolizable ketones: Reaction 3. 37 The BWR cleaves diaryl ketones cleanly and in high yields under much milder conditions. The cleavage of unsymmetrical diaryl ketones is a key part of the present work.…”

Investigations into the primary structure of feather keratin

“…According to the Bauer-Hal 1er mechanism (Hamlin and Weston, 1957) the meta-stable adduct can decompose either by cleavage of the amide bond to form the amine and the corresDonding acid hydrazide (C) or by cleavage of the carbon-carbon bond to form a hydrazone (D).…”