1.13 Intramolecular Hydrogen-Atom Transfer

Recent advances in intramolecular hydrogen-atom transfer (HAT) have demonstrated significant utility in C—H functionalization through highly reactive open-shell intermediates. The intramolecular transposition of radical reactivity from select functional groups to generate more stable carbon-centered radicals often proceeds with high regioselectivity, providing novel bond disconnections at otherwise inert and largely indistinguishable positions. This chapter explores the functional groups capable of intramolecular HAT to generate remote radicals and the transformations currently available to the synthetic chemist.

DFT study on Ir-quinoid catalyzed C–H functionalization: new radical reactivity or direct carbene transfer?

We use DFT methods to explore the mechanism of a direct C(sp3)–H functionalization via metal quinoid carbenes.

Modulating the radical reactivity of phenyl radicals with the help of distonic charges: it is all about electrostatic catalysis

This manuscript reports the electrostatic nature of the modulation of H-abstraction reactivity of phenyl radicals by (positive and negative) distonic ions.

Diazaphospholenes as Reducing Agents: A Thermodynamic and Electrochemical DFT Study

Diazaphospholenes have emerged as a promising class of metal-free hydride donors and have been implemented as molecular catalysts in several reduction reactions. Recent studies have also verified their radical reactivity...

Recent advances in Minisci-type reactions and applications in organic synthesis

Abstract:: Minisci-type reactions have become widely known as reactions that involve the addition of carbon-centered radicals to basic heteroarenes followed by formal hydrogen atom loss. While the originally developed protocols for radical generation remain in active use today, in recent years by a new array of radical generation strategies allow use of a wider variety of radical precursors that often operate under milder and more benign conditions. New transformations based on free radical reactivity are now available to a synthetic chemist looking to utilize a Minisci-type reaction. Radical-generation methods based on photoredox catalysis and electrochemistry, which utilize thermal cleavage or the in situ generation of reactive radical precursors, have become popular approaches. Our review will cover the remarkably literature that has appeared on this topic in recent 5 years, from 2015-01 to 2020-01, in an attempt to provide guidance to the synthetic chemist, on both the challenges that have been overcome and applications in organic synthesis.

New insights into secondary organic aerosol from nitrate oxidation of isoprene in the atmospheric simulation chamber SAPHIR

<p>Experiments at a set of atmospherically relevant conditions were performed in the atmospheric simulation chamber SAPHIR, investigating the oxidation of isoprene by the nitrate radical (NO3). A comprehensive set of instruments detected trace gases, radicals, aerosol properties and hydroxyl (OH) and NO3 radical reactivity. The chemical conditions in the chamber were varied to change the fate of the peroxy radicals (RO2) formed after the reaction between NO3 and isoprene, and seed aerosol of varying composition was added to initiate gas/aerosol partitioning. This presentation discusses observed gas/aerosol partitioning of the major organic nitrate products and summarizes the observations of secondary organic aerosol yield.</p>