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.