Organotransition metal catalyzed cycloaddition

摘要

Transition metal catlyzed cycloaddition and related carbon-carbon bond forming reactions are described.Zerovalent palladium species catlyze the cyclocuplig between two molecules of electron-deficient alkynes or 1,6-diynes and alkenes or alkynes.Intramolecular [2+2+2] cycloaddition of dimethyl 5,10-dioxa-tetradeca-2,7,12triynediolate induces bis-annulation of 2,5-dihydrofuran to give the corresponding phthalate derivative involving two 2,5-dihydrofuran moieties.In stoichimetric reaction with Pd_2(dpa)_3,the triyne furnishes a planar three-coordinated triyne complex of palladium.The cationic pentamethylcyclopentadienylruthenium (II)fragment,CpRu(Cp velence #eta#~5-C_5Me_5)induces [4+4] cycloaddition of butadiene nd isoprene.The pentamethylcyclopentadi-enylruthenium(II) chloride fragment,CpRuCl,is a highly efficient catlyst to induce [2+2+2]cycloaddition of 1,6-diynes with several carbon-carbon and carbon-nitrogen multiple bonds to furnish bicyclic arenes,cyclohexadienes,pyridines,2,2'-dipyridyl derivatives,and pyridones fused by cyclopentne,2,5-dihydrofuran or pyrrolidine moieties.An indenylchlororuthenium(II) fragment induces unprecedented catlytic bis-cyclopropanation in the reaction of 1,6-diynes with strained bicycloalkenes.