62415-74-1Relevant articles and documents
Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
, p. 3860 - 3865 (2018/04/26)
Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
Regioselectivity in the aryne cross-coupling of aryllithiums with functionalized 1,2-dibromobenzenes
Diemer, Vincent,Begaud, Manon,Leroux, Frederic R.,Colobert, Fracoise
experimental part, p. 341 - 354 (2011/02/28)
Tri- and tetrasubstituted ortho-bromobiaryls have been synthesized in good-to-excellent yields by aryne cross-coupling reactions starting from 1,3-dimethoxybenzene and functionalized 1,2-dibromobenzenes. This study outlines the influence of the 1,2-dibromobenzene precursor as well as the reaction temperature on the outcome of the aryl-aryl bond formation and indicates, in the case of dissymmetrical benzyne precursors, how structural parameters (electronic effects, steric hindrance, temperature, etc.) control the regioselectivity of the aryne cross-coupling reactions. A wide range of o,o′-tri- and-tetrasubstituted biphenyls have been prepared by a transition-metal-free "aryne" cross-coupling starting from 2,6-dimethoxyphenyllithium and various functionalized 1,2-dibromobenzenes. Mechanistic investigations outline the key parameters that govern both the aryl-aryl bond formation and the regioselectivity of the reaction with dissymmetrical aryne precursors. Copyright
POLYBROMINATED AROMATIC COMPOUNDS. IV. METHOXYDEBROMINATION REACTIONS OF POLYBROMOBENZENES IN PYRIDINE
Shishkin, V. N.,Lapin, K. K.,Tanaseichuk, B. S.,Butin, K. P.
, p. 516 - 522 (2007/10/02)
The rates were measured and the orientation was studied for the methoxydebromination of all polybromobenzenes C6HnBr6-n (n = 0-3) in pyridine at 115 deg C.From comparison of the partial rates of substitution of the bromine atom at various positions of the benzene ring it was found that the activating effect of the bromine atom in relation to the point of nucleophilic attack changes in the order o-Br > m-Br > p-Br, and the directing selectivity of the bromine is low (compared with fluorine in the methoxydefluorination of polyfluorobenzenes) and increases with decrease in the number of bromine atoms in the aromatic ring of the substrate.
