Vinylation of Unprotected Phenols Using a Biocatalytic System.

Readily available substituted phenols were coupled with pyruvate in buffer solution under atmospheric conditions to afford the corresponding para-vinylphenol derivatives while releasing only one molecule of CO2 and water as the by-products. This transformation was achieved by designing a biocatalytic system that combines three biocatalytic steps, namely the C-C coupling of phenol and pyruvate in the presence of ammonia, which leads to the corresponding tyrosine derivative, followed by deamination and decarboxylation. The biocatalytic transformation proceeded with high regioselectivity and afforded exclusively the desired para products. This method thus represents an environmentally friendly approach for the direct vinylation of readily available 2-, 3-, or 2,3-disubstituted phenols on preparative scale (0.5 mmol) that provides vinylphenols in high yields (65-83 %).