Photoinitiated electron transfer-substitution reaction of diphenyl ketyl with protonated 4-cyanopyridine

Nucleophilic character of the alkyl radicals. 16. Absolute rate constants and the reactivity-selectivity relationship in the homolytic aromatic alkylation

“…6 Peroxide (10~2 M); CuOAc (1.6 1()-3 M); H2S04 (2 M).1 Peroxide ( "2 M); CuOAc (1.6 10~3 M); H2S04 (1 M). 16 Peroxide (10~3 M); CuOAc (5 X "4 M); H2S04 (1 M). DMCS; 15 ft X >/5 in.…”

Exploiting Transient Radical Cations as Brønsted Acids for Allylic C–H Heteroarylation of Enol Silyl Ethers

“…Considering the high acidity of the radical cations, we reasoned that this class of intermediates could be utilized as catalytically generated Brønsted acids for the activation of electrophiles having a basic functionality via protonation, which would concomitantly generate nucleophilic radicals for bond formation with the activated electrophiles. As electrophilic substrates suitable for assessing the viability of this hypothesis, we chose cyanopyridines because (i) they could be readily protonated by the radical cations and (ii) the resulting pyridinium ion would undergo single‐electron reduction and subsequent radical‐radical coupling in a facile manner (Scheme 1b) [10,11] . Herein, we describe the successful implementation of this scenario in the development of an allylic heteroarylation of enol silyl ethers with heteroarylcyanides under visible‐light photoredox catalysis (Scheme 1b).…”

“…As electrophilic substrates suitable for assessing the viability of this hypothesis, we chose cyanopyridines because (i) they could be readily protonated by the radical cations and (ii) the resulting pyridinium ion would undergo single-electron reduction and subsequent radicalradical coupling in a facile manner (Scheme 1b). [10,11] Herein, we describe the successful implementation of this scenario in the development of an allylic heteroarylation of enol silyl ethers with heteroarylcyanides under visible-light photoredox catalysis (Scheme 1b).…”

Direct Hydroxylarylation of Benzylic Carbons (sp3/sp2/sp) via Radical-Radical Cross-Coupling Powered by Paired Electrolysis

“…Hence, we speculated as follows: the carbocation is nucleophilically attacked by water to form the corresponding benzylic alcohol, which is then further oxidized at the anode to generate the ketyl radical 27 . And at the counter electrode, the well-studied classic radical precursor 1,4-DCB 28 generates the persistent radical anion via reductive SET. Finally, radical intermediates formed at the anode and cathode undergo radical-radical cross-coupling.…”