BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.177.157//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20240516T024041EDT-9649vPVJTp@132.216.177.157 DTSTAMP:20240516T064041Z DESCRIPTION:Radical reactions are routinely considered in synthetic plannin g\, and highly active research continues on new ways to make and use radic als. Because the products of radical-molecule reactions are again radicals \, such processes are perfectly suited to be run as sequential reactions ( cascades). Likewise\, because radicals can be oxidized or reduced\, radica l-ionic crossover reactions can be implemented. Such cascade reactions ser ve well the goal of step economy in organic synthesis. As compared to non- radical processes\, most radical reactions are very fast. Radical chain re actions require only a small amount of an initiator and addition of a cata lyst is generally not necessary. Therefore\, it is often difficult to cata lyze radical transformations since background chain reactions are so fast. [1]\n\nIn the lecture the concept of using the electron as a catalyst will be discussed.[1\,2] It will be shown that the electron is an efficient ca talyst for conducting various types of radical cascade reactions that proc eed via radical and radical ion intermediates. The “electron is a catalyst ” paradigm unifies mechanistically an assortment of synthetic transformati ons that otherwise have little or no apparent relationship. Some recent ex amples on the use of the electron as a catalyst will be discussed.[3]\n\nI t will be emphasized how a negative charge can significantly weaken the ne ighbouring C-H bond and activate this bond towards H-atom transfer.[3e\,j] Moreover\, the activation of a C-H bond next to a C-radical towards depro tonation is a key point in the field of electron-catalysis. This issue wil l be addressed in the lecture. Extending that concept\, the use of a negat ive charge to activate a C-C sigma-bond towards homolysis is also discusse d.[3i\,k] For example\, electron catalyzed transition metal-free b-alkenyl ation-a-perfluoroalkylation of unactivated alkenes via radical 1\,4 or 1\, 5-alkenyl migration will be presented. Electrochemistry can be applied to initiate electron-catalyzed processes.[3m]\n\nIt will be further shown\, t hat readily generated vinyl boron ate complexes\, generally used as substr ates in the Suzuki-Miyaura coupling\, are efficient radical acceptors to c onduct electron-catalyzed modular synthesis comprising a radical polar cro ss over step.[3h] This approach has recently been successfully applied to the development of a novel method for the preparation of highly enantioenr iched a-chiral ketones[3l] and a new method for radical borylation is disc ussed.[3n]\n\nReferences\n\n[1] A. Studer\, D. P. Curran\, Angew. Chem. In t. Ed. 2016\, 55\, 58-102.\n [2] A. Studer\, D. P. Curran\, Nature Chem. 20 14\, 6\, 765-773.\n [3] (a) B. Zhang\, A. Studer\, Org. Lett. 2014\, 16\, 3 990-3993. (b) D. Leifert\, A Studer\, Org. Lett. 2015\, 17\, 386-389. (c) M. Hartmann\, C. G. Daniliuc\, A. Studer\, Chem. Commun. 2015\, 51\, 3121- 3123. (d) D. Leifert\, D. G. Artiukhin\, J. Neugebauer\, A. Galstyan\, C. A. Strassert\, A. Studer\, Chem. Commun. 2016\, 52\, 5997-6000. (e) A. Dew anji\, C. Mück-Lichtenfeld\, A. Studer\, Angew. Chem. Int. Ed. 2016\, 55\, 6749-6752. (f) J. Xuan\, C. G. Daniliuc\, A. Studer\, Org. Lett. 2016\, 1 8\, 6372–6375. (h) M. Kischkewitz\, K. Okamoto\, C. Mück-Lichtenfeld\, A. Studer\, Science 2017\, 355\, 936-938. (i) X. Tang\, A. Studer\, Chem. Sci . 2017\, 8\, 6888-6892. (j) T. Hokamp\, A. Dewanji\, M. Lübbesmeyer\, C. M ück-Lichtenfeld\, E.-U. Würthwein\, A. Studer\, Angew. Chem. Int. Ed. 2017 \, 56\, 13275-13278. (k) X. Tang\, A. Studer\, Angew. Chem. Int. Ed. 2018\ , 57\, 814-817. (l) C. Gerleve\, M. Kischkewitz\, A. Studer\, Angew. Chem. Int. Ed. 2018\, 57\, 2441-2444. (m) M. Lübbesmeyer\, D. Leifert\, H. Schä fer\, A. Studer\, Chem. Commun. 2018\, 54\, 2240-2243. (n) Y. Cheng\, C. M ück-Lichtenfeld\, A. Studer\, J. Am. Chem. Soc. 2018\, 140\, 6221-6225.\n DTSTART:20180904T170000Z DTEND:20180904T183000Z LOCATION:Room 10\, Maass Chemistry Building\, CA\, QC\, Montreal\, H3A 0B8\ , 801 rue Sherbrooke Ouest SUMMARY:CCVC/Chemical Society Seminar: Armido Studer - Electron Catalysis URL:https://www.mcgill.ca/channels/channels/event/ccvcchemical-society-semi nar-armido-studer-electron-catalysis-288492 END:VEVENT END:VCALENDAR