65171-07-5Relevant academic research and scientific papers
Photochemical generation of radicals from alkyl electrophiles using a nucleophilic organic catalyst
Schweitzer-Chaput, Bertrand,Horwitz, Matthew A.,de Pedro Beato, Eduardo,Melchiorre, Paolo
, p. 129 - 135 (2018/12/13)
Chemists extensively use free radical reactivity for applications in organic synthesis, materials science, and life science. Traditionally, generating radicals requires strategies that exploit the bond dissociation energy or the redox properties of the precursors. Here, we disclose a photochemical catalytic approach that harnesses different physical properties of the substrate to form carbon radicals. We use a nucleophilic dithiocarbamate anion catalyst, adorned with a well-tailored chromophoric unit, to activate alkyl electrophiles via an SN2 pathway. The resulting photon-absorbing intermediate affords radicals upon homolytic cleavage induced by visible light. This catalytic SN2-based strategy, which exploits a fundamental mechanistic process of ionic chemistry, grants access to open-shell intermediates from a variety of substrates that would be incompatible with or inert to classical radical-generating strategies. We also describe how the method’s mild reaction conditions and high functional group tolerance could be advantageous for developing C–C bond-forming reactions, for streamlining the preparation of a marketed drug, for the late-stage elaboration of biorelevant compounds and for enantioselective radical catalysis.
SYNTHESES TOTALES ET ETUDES DE LIGNANES BIOLOGIQUEMENT ACTIFS-I. APPLICATION DE LA REACTION D'ULLMANN A LA SYNTHESE DE BIARYLES PRECURSEURS DE LIGNANES BISBENZOCYCLOOCTADIENES
Brown, Eric,Robin, Jean-Pierre,Dhal, Robert
, p. 2569 - 2580 (2007/10/02)
Several biaryls bearing various substituents on both rings were synthesized in a preparativ fashion, and in yields up to 88percent by a technical improvement on the classical Ullmann reaction.All these biaryls bear reactive functional groups (i.e. formyl, methoxycarbonyl, dimethoxycarbonylpropyl and butanolidylmethyl) in both the o and o' positions.The biaryls 9, 13, 21 and 26-33 are plausible synthons for bisbenzocyclooctadiene lignans such as schizandrin and steganacin.
