Trifluoroacetic Anhydride Mediated One-Pot Synthesis of 1-Aryl Isochroman-3-ones via the Carboxy-Pictet-Spengler Reaction.

In this paper, a novel and open-vessel route for the facile-operational synthesis of 1-aryl isochroman-3-ones is described via (CF3CO)2O (trifluoroacetic anhydride, TFAA)-mediated intermolecular (4 + 2) annulation of oxygenated arylacetic acids with arylaldehydes or ketones under mild reaction conditions. A plausible mechanism is proposed and discussed herein. Various reaction conditions are investigated for efficient transformation under an environmentally friendly one-pot carboxy-Pictet-Spengler reaction.