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1,3‐Dipolar Cycloaddition Reactions Initiated with the 1,5‐Dimethyl‐3‐phenyl‐6‐oxoverdazyl Radical
Author(s) -
Yang Angela,
Kasahara Takahito,
Chen Eric K. Y.,
Hamer Gordon K.,
Georges Michael K.
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200800687
Subject(s) - chemistry , cycloaddition , acrylate , radical , dimethyl fumarate , styrene , 1,3 dipolar cycloaddition , ethyl acrylate , imine , methyl acrylate , polymer chemistry , photochemistry , organic chemistry , medicinal chemistry , monomer , catalysis , polymer , psychology , copolymer , psychiatry , multiple sclerosis
Abstract The 1,5‐dimethyl‐3‐phenyl‐6‐oxoverdazyl radical reacts at room temperature in the presence of styrene to give a dihydrotetrazinone heterocyclic structure. We surmise that the reaction occurs by a 1,3‐dipolar cycloaddition via the intermediacy of an azomethine imine. While initial reactions under nitrogen gave relatively poor yields (40 %) of the cycloaddition product, improved yields (up to 84 %) were realized when the reaction mixtures were saturated with oxygen. Acrylate, methacrylate, fumarate and maleate dipolarophiles react regioselectively and stereospecifically to provide a series of dihydrotetrazinone heterocyclic structures. These initial results demonstrate the feasibility of using verdazyl radicals as substrates for organic synthesis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)