Synthesis of Enantiomerically Pure Polyfluorobenzo[d]sultams

Polyfunctionalized benzo[d]sultams which contain an amino acid unit, have been synthesized from the corresponding open chain (pentafluorobenzene)sulfonamides by complementary solid-liquid phase transfer catalysis (SL-PTC) and homogeneous protocols. The cyclization step proceeds through the intramolecular nucleophilic displacement of an aromatic fluorine atom and leeds to the desired product with good ee's (50-88%) without any external source of chirality. The described procedure, toghether with the preferential crystallization of all the compounds allows the obtainment of optically pure benzosultams.