Pd/C-catalyzed dehydrogenation of 2-cinnamoylbenzoic acids to 3-benzylidene-3H-isochroman-1,4-diones.

Pd/C, a widely accepted hydrogenation catalyst, is found to catalytically dehydrogenate 2-cinnamoylbenzoic acids to 3-benzylidene-3-H-isochroman-1,4-diones with H-2 as the only byproduct. This synthetic reaction proceeds without oxidants and hydrogen acceptors, thereby representing an atom- and step-efficient approach to a wide range of functionalized 3-benzylidene-3H-isochroman-1,4-diones.