Photo-mediated synthesis of halogenated spiro[4,5]trienones of <i>N</i>-aryl alkynamides with PhI(OCOCF<sub>3</sub>)<sub>2</sub> and KBr/KCl
Tong Liu, Yaming Li, Linlin Jiang, Jiaao Wang, Kun Jin, Rong Zhang, Chunying Duan
Abstract
A novel and convenient photo-mediated halogenated spirocyclization of N-(p-methoxyaryl)propiolamides has been developed. The photolysis of phenyliodine bis(trifluoroacetate) (PIFA) as an iodination reagent led to iodinated ipso-cyclization under the irradiation of a xenon lamp, while brominated ipso-cyclization or chlorinated ipso-cyclization was achieved by irradiating a mixture of PIFA and KBr/KCl under a blue LED. The present protocol simply utilizes light as the safe and clean energy source and doesn't require any external photocatalyst providing various 3-halospiro[4,5]trienones in good to excellent yields (up to 93%).
Topics & Concepts
HalogenationReagentPhotodissociationChemistryArylIrradiationRadiochemistryXenonNuclear chemistryPhotochemistryOrganic chemistryAlkylPhysicsNuclear physicsOxidative Organic Chemistry ReactionsRadical Photochemical ReactionsSulfur-Based Synthesis Techniques