Styrene compounds hydrocarboxylation

The hydrocarboxylation of styrene (Scheme 5.12) and styrene derivatives results in the formation of arylpropionic acids. Members of the a-arylpropionic acid family are potent non-steroidal anti-inflammatory dmgs (Ibuprofen, Naproxen etc.), therefore a direct and simple route to such compounds is of considerable industrial interest. In fact, there are several patents describing the production of a-arylpropionic acids by hydroxycarbonylation [51,53] (several more listed in [52]). The carbonylation of styrene itself serves as a useful test reaction in order to learn the properties of new catalytic systems, such as activity, selectivity to acids, regioselectivity (1/b ratio) and enantioselectivity (e.e.) in the branched product. In aqueous or in aqueous/organic biphasic systems complexes of palladium were studied exclusively, and the results are summarized in Table 5.2. 

In spite of intensive efforts by numerous research groups, practically efficient methods for the asymmetric hydrocarboxylation have not yet been reported. Styrene and other vinylaromatics are most widely examined and the data for representative examples are summarized in Scheme 16 and Table 4 (see Structure 2 for catalysts). The products are of much interest as synthetical intermediates for bioactive compounds. Although some of the reports reach high ees, the studies are still on their way to be completed. 

The hydrocarboxylation of styrene (Scheme 5.12) and styrene derivatives results in the formation of arylpropionic acids. Members of the a-arylpropionic acid family are potent non-steroidal anti-inflammatory drags (Ibuprofen, Naproxen etc.), therefore a direct and simple route to such compounds is of considerable industrial interest. In fact, there are several patents describing the production of a-arylpropionic acids by... 

Recent progress in palladium(II) chloride catalyzed hydrocarboxylations is reported for the conversion of styrenes to give optically active free carboxylic acids24,25. The reactions are conducted in the presence of a protic acid, copper(II) chloride, oxygen, and a single enantiomer of an optically active compound selected from menthol, tartaric acid or ester, sugars, proteins, polypeptides, enzymes and chiral phosphanes. 

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