Ferulic　acid　dissolved　in　water　is　selectively　oxidized　to　vanillic　acid　in　high　yield　(approximate　to　60%)　under　remarkably　mild　and　green　conditions,　namely　at　room　temperature　with　air　as　primary　oxidant,　over　a　catalytic　amount　of　nanostructured　Bi2WO6.　The　process　is　general　and　opens　the　route　to　the　selective　oxidation　of　natural　substances　into　derivatives　of　significant　applicative　relevance.