Facile Regioselective Synthesis of Functionalized Heterocycle-Tethered Spiro Compounds via an Intramolecular Electrophilic Ipso-Iodocyclization Process

摘要

A general, regioselective, and efficient intramolecular electrophilic ipso-iodocyclization of a series of N-alkyl-N-aryl phe-nylpropiolamides in the presence of I_2 (molecular iodine) and NaHCO_3 via 5-endo-dig mode of cyclization has been developed for the synthesis of hitherto unreported coumarin, quinolone, and pyrimidine-annelated heterocyclic compounds in excellent yields (84-92%). The development of this methodology provides efficient and mild reaction conditions that allow for easy isolation of prod-ucts. The synthesized Spiro derivatives offer an attractive and useful scope for further functionalization and to synthesize new bioactive heterocycles.