Synthesis of α-ester–β-keto peroxides via iron-catalyzed carbonylation–peroxidation of α,β-unsaturated esters

Recent advances in acyl radical enabled reactions between aldehydes and alkenes

Radical-mediated functionalization of alkenes has been emerging as an elegant and straightforward protocol to increase molecule complexity. Moreover, the abstraction of a hydrogen atom from aldehydes to afford acyl radicals has evolved as a rising star due to its high atom-economy and the ready availability of aldehydes. Considering the great influence and synthetic potential of acyl radical enabled reactions between aldehydes and alkenes, we provide a summary of the state of the art in this field with a specific emphasis on the working models and corresponding mechanisms. The discussion is divided according to the kind of alkenes and reaction type.

Organocatalytic Enantioselective γ-Elimination: Applications in the Preparation of Chiral Peroxides and Epoxides

An organocatalyzed enantioselective γ-elimination process has been achieved and applied in the kinetic resolution of peroxides to access chiral peroxides and epoxides. The reaction provided a pathway for the preparation of two useful synthetic and biologically important structural motifs through a single-step reaction. A range of substrates has been resolved with a selectivity factor up to 63. The obtained enantioenriched peroxides and epoxides allowed a series of transformations with retained optical purities.

Heat- or light-induced acylarylation of unactivated alkenes towards 3-(α-acyl) indolines

A heat- or photoredox/iron dual catalysis-enabled rare example of radical acylation across unactivated alkenes with aldehydes.

Copper-catalyzed trifluoromethylthiolation-peroxidation of alkenes and allenes

Cu-catalyzed trifluoromethylthiolation-peroxidation of alkenes and allenes using AgSCF₃ and tert-butyl hydroperoxide has been developed. The method provides a variety of β-SCF₃ and β-vinyl-SCF₃ peroxides with excellent regio- and chemo-selectivities.

The Persistent Radical Effect in Organic Synthesis

Radical-radical couplings are mostly nearly diffusion-controlled processes. Therefore, the selective cross-coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if the radicals have different lifetimes and if they are generated at equal rates, cross-coupling will become the dominant process. This high cross-selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this Review, an explanation of the PRE supported by simulations of simple model systems is provided. Radical stabilities are discussed within the context of their lifetimes, and various examples of PRE-mediated radical-radical couplings in synthesis are summarized. It is shown that the PRE is not restricted to the coupling of a persistent with a transient radical. If one coupling partner is longer-lived than the other transient radical, the PRE operates and high cross-selectivity is achieved. This important point expands the scope of PRE-mediated radical chemistry. The Review is divided into two parts, namely 1) the coupling of persistent or longer-lived organic radicals and 2) "radical-metal crossover reactions"; here, metal-centered radical species and more generally longer-lived transition-metal complexes that are able to react with radicals are discussed-a field that has flourished recently.

Four-component radical-dual-difunctionalization (RDD) and decarbonylative alkylative peroxidation of two different alkenes with aliphatic aldehydes and TBHP

From difunctionalization of a single alkene to radical-dual-difunctionalization of two different alkenes! A alkylative peroxidation and cross-coupling of two alkenes was established with the aliphatic aldehydes as the alkyl radical source.

Simultaneous voltammetric determination of guanine and adenine by using a glassy carbon electrode modified with a composite consisting of carbon quantum dots and overoxidized poly(2-aminopyridine)

A composite consisting of carbon quantum dots (CQDs) and overoxidized poly(2-aminopyridine) (PAPox) was deposited on a glassy carbon electrode (GCE) through electrochemical polymerization and electrochemical oxidation. The modified GCE was used for the simultaneous determination of guanine and adenine. Electrochemical responses to guanine and adenine were investigated by cyclic voltammetry and differential pulse voltammetry. Owing to the synergistic effect of CQDs and PAPox, two oxidation peaks can be observed, with peaks at 0.81 and 1.13 V (vs. SCE) for guanine and adenine, respectively. The current at the respective peaks has a linear dependence on the concentrations of guanine in the range from 1.0 to 65 μM, and of adenine in the range from 2.0 to 70 μM. The respective detection limits are 0.51 and 0.39 μM (at an S/N ratio of 3). The modified GCE is selective, reproducible and stable. Graphical abstract Schematic of the preparation of a glassy carbon electrode modified with carbon quantum dots and overoxidized poly(2-aminopyridine (CQD/PAPox/GCE), and its application for the simultaneous determination of guanine and adenine.

Copper-catalyzed three-component phosphorylation–peroxidation of alkenes

A copper-catalyzed three-component phosphorylation–peroxidation of alkenes with P(O)–H compounds and TBHP has been developed.

Alkylation–peroxidation of α-carbonyl imines or ketones catalyzed by a copper salt via radical-mediated Csp3–H functionalization

The catalytic alkylation–peroxidation of α-carbonyl imines or ketones was enabled by a simple copper salt via radical-mediated C_sp3–H functionalization.

Total Synthesis and Structure Revision of (±)-Clavilactone D Through Selective Cyclization of an α,β-Dicarbonyl Peroxide

The structure of (±)-clavilactone D was revised, and the synthesis was achieved in seven steps from a substituted benzaldehyde. The key step was the base-catalyzed cyclization of an α,β-carbonyl peroxide, which was obtained by an iron-catalyzed three-component reaction of a benzaldehyde, an alkene, and TBHP. NaBH₄-mediated reductive lactonization of the resulting cis-dicarbonyl epoxide led to the α,β-epoxy-γ-butyrolactone skeleton highly stereoselectively. The synthesis provides a concise, reliable, and practical route to the revised structure of clavilactone D.

Direct coupling of sp3 carbon of alkanes with α,β-unsaturated carbonyl compounds using a copper/hydroperoxide system

A new methodology of monovalent copper-initiated direct coupling of alkanes and hydroperoxides with unsaturated carbonyl compounds is developed.

Iron-catalyzed peroxidation–carbamoylation of alkenes with hydroperoxides and formamides via formyl C(sp2)–H functionalization

A three-component radical coupling reaction of aryl alkenes or 1,3-enynes with tert-butyl hydroperoxide and formamides for the efficient synthesis of β-peroxy amides.

Cobalt salt-catalyzed carbocyclization reactions of α-bromo-N-phenylacetamide derivatives

A Co(ii)-catalyzed carbocyclization reaction for the synthesis of 4-substituted quinolin-2-(1H)-ones is described.

Advances in the synthesis of acyclic peroxides

This review summarises the many developments in the synthesis of acyclic peroxides, with a particular focus on the past 20 years, and seeks to update organic chemists about these new approaches.

A transition-metal-free, one-pot procedure for the synthesis of α,β-epoxy ketones by oxidative coupling of alkenes and aldehydes via base catalysis

A new strategy for the synthesis of epoxides is presented. This process allows the direct synthesis of epoxides from alkenes and aldehydes through C-H functionalization and C-C/C-O bond formation.

Manganese triacetate as an efficient catalyst for bisperoxidation of styrenes

Bisperoxidation of styrenes with tert-butyl hydroperoxide in the presence of a catalytic amount of Mn(OAc)₃.

Iron-catalyzed/mediated oxidative transformation of C–H bonds

Iron-catalyzed/mediated C–H bond oxidation has been demonstrated as one of practical and straightforward tools in synthetic chemistry.