A new efficient synthesis of isoquinoline-1,3(2H,4H)-diones or isoindolin-1-ones via sequential Ugi-4CR or Ugi-3CR/cyclization reaction was developed. α-Acylamino amides 5, obtained from Ugi-4CR of methyl 2-formylbenzoate, amines, isocyanates and acids, cyclized to give isoquinoline-1,3(2H,4H)-diones 6 in good yields in the presence of catalytic amount of sodium ethoxide. Ugi-3CR of methyl 2-formylbenzoate, amines and isocyanates in the presence of catalytic amount of H3P...
