Synthetic Aspects of Photochemical Electron Transfer Reactions

Photoinduced electron transfer oxygenations

“…The produced radical ions, in virtue of their dual functionality: ionic and radical, may back transfer the electron to restore Sens and D ground states or may go on to produce several new reaction products in relation to the reaction conditions [69][70][71][72]75]. The feasibility of a photochemical electron-transfer reaction between an excitedstate sensitizer and a quencher is dictated by the overall change in free energy AG which accompanies the reaction.…”

“…On the other hand, because this area is inherently interdisciplinary, it is rather hard to provide a detailed compilation of all work relevant to the photoinduced reactions of concern. Thus, except for few cases, no attempt will be made to discuss the diversified chemistry of photosensitized electron-transfer processes, extensively reported in several excellent reviews [69][70][71][72].…”

Addition and cycloaddition reactions via photoinduced electron transfer

“…Mariano and his coworkers developed the intra-and intermolecular photoadditions of the radical cations and the radicals derived from them to the = N-C ° radical [130][131][132]. Although they are summarized in his review article [3,[133][134][135], some examples are shown in Scheme 44. The photoaddition of allylic or benzylic radicals to the = N-C ° radical can be achieved by the photoreaction of iminium compounds with group 14 organometallic compounds bearing allylic and benzylic groups.…”

“…Photoinduced electron transfer reactions are a useful method, particularly for generation of radical ion species [1][2][3][4][5][6][7][8][9][10]. Radical ions can also be generated by electrochemical method or by redox reactions using metal compounds with low or high redox potentials.…”

Control of Chemoselectivity of SET-Promoted Photoaddition Reactions of Fullerene C60 with α-Trimethylsilyl Group-Containing N-Alkylglycinates Yielding Aminomethyl-1,2-dihydrofullerenes or Fulleropyrrolidines

“…Among the variety of organic substances that participate in photoinduced single-electron transfer (SET) processes, aliphatic/aromatic amines have a long abundant history as readily oxidized ( E ox < 1 V vs saturated calomel electrode (SCE)) electron donors that undergo photoaddition reactions with a host of different electron acceptors. − In these photochemical reactions, amine radical cations 2 (i.e., aminium radicals) generated by SET from amines serve as key reactive intermediates, ,, which undergo diverse reactions including energy-wasting back SET to reform the ground state of donors and acceptors and base-promoted deprotonation at α-carbons to form α-amino radicals 3 – 4 (path A in Scheme ). ,,, Electron-rich α-amino radicals formed in this manner participate in radical coupling or nucleophilic addition to electron-deficient olefins, cyanoarenes, and α,β-unsaturated ketones. ,,, Another common viable route for aminium radicals 2 is hydrogen atom transfer (HAT) from α-carbons to produce iminium ions 5 – 6 (path B in Scheme ), ,, which also arise by SET from the readily oxidized α-amino radical intermediates 3 – 4 ( E ox = ca.…”