Chiral analysis halogenated

Heteroaromatic sulfoxides and sulfones ligand exchange and coupling in sulfuranes and /pro-substitutions, 49, I Heteroaromatic systems, Claisen rearrangements in, 42, 203 Heteroaromatics, quantitative analysis of steric effects in, 43, 173 Heterocycles aromaticity of, 17, 255 chiral induction using, 45, 1 containing the sulfamide moiety. 44, 81 halogenation of, 7, 1 57, 291 58, 271 59, 245... 

Strains of Pseudomonas putida are very versatile in metabolizing aromatic compounds, particularly to the corresponding 1,2-dihydro-l,2-diols. The hydroxylating enzyme of the P. putida mutant is not strongly substrate specific and alkyl, aryl and halogen functionalities are usually readily tolerated380. Thus, 4-bromobenzoic acid (1, R = Br) is converted to a. v-4-bro-mo-5,6-dihydroxy-l, 3-cyclohexadiene-l-carboxylic acid (2, R = Br) in 80% yield with 98% cc (determined by chiral NMR shift experiments on the 4-nitrobenzyl ester) 375. The absolute stereochemistry, (5R,6R), was determined by a single crystal X-ray analysis. 

Another interesting aspect of the model reactions has been reported for copper-mediated processes.273 Thus, optically active methyl 2-bromopropionate was mixed with a CuCl catalyst, and the reaction was followed by NMR and polarimetry. The latter analysis showed, as in solvolysis, that the model quickly undergoes racemization i.e., the halogen on the chiral carbon dissociates and recouples. 

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