Direct Evidence of Cis Addition in the Catalytic Hydrocarboxylation of Acenaphthylene to Acenaphthene-1-carboxylic Acid

Abstract

The hydrocarboxylation of acenaphthylene with the [PdCl2(CH3CN)2] + nPAr3 catalytic system gave good yields of acenaphthene-1-carboxylic acid, after it was found that the chemoselectivity over oligomeric side products is highly dependent on the electronic characteristics of the phosphine and the P/Pd ratio. Deuteriocarboxylation of this substrate has been found useful to determine the diastereoselectivity of this type of reaction, owing to the structure of the product. A series of results showed that hydrocarboxylation of acenaphthylene with oxalic acid and CO at 30 bar is highly diastereoselective in the cis isomer under all tested conditions but one.