Unexpected reactions of organozinc reagents with N-acylbenzotriazoles

Abstract

Coupling N-acylbenzotriazoles with aliphatic and benzylic organozinc reagents in the presence of zinc bromide / Pd(II) catalyst (or zinc bromide / Ni(0) catalyst) did not result in formation of the expected ketones, but instead gave the corresponding carboxylic acid esters. This reaction apparently occurs by the insertion of oxygen dissolved in the solvent into the organozinc compound.

Epigenetic Modifiers Induce Bioactive Phenolic Metabolites in the Marine-Derived Fungus Penicillium brevicompactum

“…Bioactive fungal extract derived from nicotinamide treatment were further purified by Sephadex LH20 followed by reversed-phase C 18 column chromatography to isolate nine compounds. These compounds were identified as p -anisic acid ( 1 ) [ 22 ], p -anisic acid methyl ester ( 2 ) [ 23 ], benzyl anisate ( 3 ) [ 24 ], syringic acid ( 4 ) [ 25 ], sinapic acid ( 5 ) [ 26 ], acetosyringone ( 6 ) [ 25 ], phenyl acetic acid ( 7 ) [ 27 ], gentisaldehyde ( 8 ) [ 28 ] and p -hydroxy benzaldehyde ( 9 ) [ 26 ] ( Figure 1 ). Chromatographic purification of fungal extract obtained from sodium butyrate treatment led to isolation of two compounds that were identified as anthranilic acid ( 10 ) [ 25 ] and ergosterol peroxide ( 11 ) [ 29 ] ( Figure 1 ).…”

Facile Syntheses of 2,2-Dimethyl-6-(2-oxoalkyl)-1,3-dioxin-4-ones and the Corresponding 6-Substituted 4-Hydroxy-2-pyrones

“…8,10 Problems with handling and storing acyl halides, and their incompatibility with acid-sensitive functional groups, prompted our search for alternatives. 11 Benzotriazole acts as a good leaving group and has been employed extensively as a synthetic auxiliary. 12 1-Acylbenzotriazoles are advantageous carboxylic acid derivatives in that they are stable and readily prepared in one step from carboxylic acids even in cases where an acid-sensitive functionality is present.…”

“…Problems with handling and storing acyl halides, and their incompatibility with acid-sensitive functional groups, prompted our search for alternatives . Benzotriazole acts as a good leaving group and has been employed extensively as a synthetic auxiliary .…”

1,2,3-Triazoles

“…1-(4-Undecyloxybenzoyl)benzotriazole 943 is conveniently used for acylation of a complex phenol in preparation of liquid crystals <2004JA1161> . Esters are also formed with good yields in reactions of 1-acylbenzotriazoles 915 with organozinc reagents in the presence of a palladium catalyst <2001ARK(xi)41> . The unusual course of these reactions must involve oxidation of the intermediates with atmospheric oxygen.…”