Radical Cyclization Reactions For Synthesis Of 2,3-dihydropyrroles

This thesis describes the applications of free radical cyclization reactions to the synthesis of 2,3-dihydropyyroles.The main contents are summarized as follows:The first chapter is a brief review on the studies of applying the iminyl radical chemistry to organic synthesis.The recent progresses made in this field are introduced from the following aspects:intromolecular addition,homolytic aromatic substitution,intramolecular hydrogen abstraction and ?-fragmentation..The second and third chapters describe the author's researchduring the periodof graduate study,which comprisesthe following two parts:?1?The reactions of ?,?-unsaturated azides with N-bromosuccinimide and N-iodosuccinimide were studied under the conditions of visible light irradiation.It was found that ?,?-unsaturated azidescan be transformed into 2,3-dihydropyrrole compounds via tandem radical halogenation/cyclization by photoredox catalysis.The reactions provide an new protocol for the preparation of brominated 2,3-dihydropyrrole compounds.?2?The reactions of ?,?-unsaturated oxime esters under visible light irradiation were explored with copper as catalyst.?,?-Unsaturated oxime esterswere successfully transformed into the corresponding iminyl radicals at room temperature by using copper complex[?DPEphos??bcp?Cu]PF₆ as catalyst.Subsequent cyclization of iminyl radicals gave rise to 2,3-dihydropyyroles.These new conditions are applicable to the synthesis of 2,3-dihydropyrroles.