The exploration of 1,2-radical shift (RS) mechanisms in photoinduced organic reactions has provided efficient routes for the generation of important radical synthons in many chemical transformations. In this Review, the basic concepts involved in the traditional 1,2-spin-center shift (SCS) mechanisms in recently reported studies are discussed. In addition, other useful 1,2-RSs are addressed, such as those proceeding through 1,2-group migrations in carbohydrate chemistry, via 1,2-boron shifts, and by the generation of α-amino radicals. The discussion begins with a general overview of the basic aspects of 1,2-RS mechanisms, followed by a demonstration of their applicability in photoinduced transformations. The sections that follow are organized according to the mechanisms operating in combination with the 1,2-radical migration event. This contribution is not a comprehensive review but rather aims to provide an understanding of the topic, focused on the more recent advances in the field, and establishes a definition for the nomenclature that has been used to describe such mechanisms.
Herein, we report a three-component organophotoredox coupling of N-alkenyl amides with α-bromocarbonyls and various nucleophiles. This transition metal-free difunctionalization protocol installs sequential C–C and C–Y (Y = S/O/N) bonds in...
The concurrent installation of C−C and C−N bonds across alkene frameworks represents a powerful tool to prepare motifs that are ubiquitous in pharmaceuticals and bioactive compounds. To construct such prevalent bonds, most alkene difunctionalization methods demand the use of precious metals or activated alkenes. We report a metal-free, photochemically mediated imino-alkylation of electronically diverse alkenes to install both alkyl and iminyl groups in a highly efficient manner. The exceptionally mild reaction conditions, broad substrate scope, excellent functional group tolerance, and facile one-pot reaction protocol highlight the utility of this method to prepare privileged motifs from readily available alkene and acid feedstocks. One key and striking feature of this transformation is that an electrophilic trifluoromethyl radical is equally efficient with both electrondeficient and electron-rich alkenes. Additionally, dispersion-corrected density functional theory (DFT) and empirical investigations provide detailed mechanistic insight into this reaction.
We present (3+ +2)-and (4+ +2)-cycloadditions of donor-acceptor (D-A) cyclopropanes and cyclobutanes with N-sulfinylamines and as ulfur diimide,a long with ao ne-pot, two-step strategy for the formal insertion of HNSO 2 into D-A cyclopropanes.These are rare examples of cycloadditions with D-A cyclopropanes and cyclobutanes whereby the 2p component consists of two different heteroatoms,thus leading to fiveand six-membered rings containing adjacent heteroatoms.
An operationally simple, open-air, and efficient light-mediated Minisci C–H alkylation method is described, based on the formation of an electron donor–acceptor (EDA) complex between nitrogen-containing heterocycles and redox-active esters.
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