Substituent effects on bromodecarboxylation reactions

Formation of Four-Membered Heterocycles through Electrophilic Heteroatom Cyclization

“…Under these conditions, intermolecular reaction products were also formed (Scheme ). Similar results were obtained by Kingsbury and Max,35b who studied the reactions between bromine and the sodium salts of substituted cinnamic acids 65 , containing a variety of substituents on the aromatic ring. When the substituent was a chloro or a methyl group, β‐lactones 66 were obtained as mixtures, the other product being compound 67 , corresponding to the addition of hypobromous acid to the olefinic double bond (Scheme ).…”

cis-β-Bromostyrene derivatives from cinnamic acids via a tandem substitutive bromination-decarboxylation sequence

“…It is presumably formed through the ring-opening nucleophilic attack on the bromonium intermediate 4 by the carboxylic acid functionality as shown in Scheme 2. 14,22 In most cases, the β-lactone intermediates can be readily isolated and even purified by column chromatography, though their purification is not required for synthetic purposes.…”

Decarboxylative Halogenation of Organic Compounds

“… 302 The similar bromination of cinnamate ion derivatives with Br 2 in water or methanol resulted in a series of products ( 658 – 662 ), the ratios and stereospecificities between them depending on the nature of the R-substituent, the solvent and the presence of NaBr ( Scheme 92 ). 303 Notably, under any conditions, the desired vinyl bromide 658 was not obtained selectively.…”

“…The formation of the lactone 682 under the conditions of the halodecarboxylation was observed previously. 303 These compounds were also isolated in preparative yields in the case of α-substituted cinnamic acid and alkylvinylcarboxylic acids. 315 , 317 …”